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Engine Room General Subjects Page 2

 

D The ability of a metal to be hammered, or rolled out is called its __________. elasticity ductility fusibility malleability Materials Science
D Reheating a hardened component to a temperature lower than the hardening temperature and then cooling it is known as __________. case hardening low temperature hardening annealing tempering Materials Science
A When hardened metal is heat-treated by a process known as tempering, what metallurgical properties are achieved? decrease in brittleness increase in hardening increase in brittleness increase in corrosion resistance Materials Science
A When metal is tempered, it becomes __________. less brittle more brittle less tough harder Materials Science
D What is the purpose of heat treating steel? Develop ductility Improve machining qualities Relieve stresses All of the above. Materials Science
A Monel metal is an alloy composed mainly of __________. nickel and copper zinc and copper bronze and tin copper and tin Materials Science
C When a metal is undergoing heat treatment, what happens when the metal is heated above its critical temperature? The metal changes from the solid state to the molten state. The metal changes from a molten state to a vapor state. The metal undergoes a change in crystalline structure. The metal undergoes thermal contraction. Materials Science
B When a metal is undergoing heat treatment for the purposes of annealing, besides refining the grain structure, what is the determining characteristic of the metal? Change in chemical composition Softened condition High tensile strength Induction of toughness Materials Science
A When a low carbon steel is undergoing heat treatment for the purposes of casehardening, what is the process that distinguishes this procedure from other hardening methods? After the steel is heated above its critical temperature, it is quenched in a carbon bath. After the steel is heated above its critical temperature, it is quenched in cold water. After the steel is heated above its critical temperature, it is allowed to cool slowly in air. After the steel is heated above its melting temperature, it is quenched in a carbon bath. Materials Science
A What effect does preheating, concurrent heating, or post heating have on welding a joint? Decreasing the temperature gradient in the weld area and relieving internal stresses. Increasing the temperature gradient in the weld area and relieving internal stresses. Decreasing the temperature gradient in the weld area and intensifying internal stresses. Increasing the temperature gradient in the weld area and intensifying internal stresses. Materials Science
D What is meant by the term tensile strength of a material? The ability to resist shearing stresses. The ability to resist bending stresses. The ability to resist compression stresses. The ability to resist stretching stresses. Materials Science
B What is meant by the term toughness as it applies to a material? The ability to resist penetration. The ability to resist repeated application and release of force. The ability to resist continuous tension. The ability to resist continuous compression. Materials Science
D Which of the following direct-reading pressure gauges is capable of measuring and displaying both positive and negative pressures? Simplex gauge Differential pressure gauge Duplex gauge Compound gauge Measuring Instruments
C If a standard bourdon tube type pressure gauge that is designed to measure and display gauge pressure reads 43.8 psig, what would be the equivalent absolute pressure? 29.1 psia 43.8 psia 58.5 psia 61.2 psia Measuring Instruments
B Which of the following direct-reading pressure gauges is capable of measuring and displaying two pressures simultaneously? Compound gauge Duplex gauge Differential pressure gauge Simplex gauge Measuring Instruments
C Which of the following direct-reading pressure gauges is capable of measuring two pressures and displaying the difference between the two? Simplex gauge Compound gauge Differential pressure gauge Duplex gauge Measuring Instruments
C Which of the following direct-reading gauges would most likely be used in the application of a pump suction pressure gauge? Differential pressure gauge Vacuum gauge Compound gauge Standard pressure gauge Measuring Instruments
D Which of the following system applications would require the use of a siphon tube (pigtail) to prevent gauge damage? Hydraulic oil pressure Heavy fuel oil Compressed air pressure Steam pressure Measuring Instruments
B When reading a pressure that fluctuates severely on a direct reading pressure gauge, what should be done? Attempt to determine the midpoint between the maximum and minimum pressures and use this as an estimate of the average pressure. The pulsation dampening needle valve should be throttled down (without closing) until the fluctuation ceases. The maximum and minimum pressures should be noted and added together and divided by two to obtain the average pressure. The pulsation dampening needle valve should be opened wider until the fluctuation ceases. Measuring Instruments
B What type of direct reading thermometer works on the principle of thermal volumetric expansion of a liquid as the temperature rises and features a linear scale? Thermocouple pyrometer Liquid-in-glass thermometer Bourdon tube thermometer Bimetallic thermometer Measuring Instruments
A If the mercury has become separated in a liquid-in-glass thermometer, what can be done to correct this situation? After removing the thermometer, hold the thermometer by the upper end and try to recombine the mercury by several full arm swings.  Repeatedly tap the side of the thermometer until the mercury recombines. After removing the thermometer, hold the thermometer by the lower end and try to recombine the mercury by several full arm swings. It is not possible to correct this situation. Measuring Instruments
A What type of direct reading thermometer works on the principle of differential expansion of dissimilar metals as the temperature rises and features a rotary dial scale? Bimetallic thermometer Liquid-in-glass thermometer Bourdon tube thermometer Thermocouple pyrometer Measuring Instruments
C What is the application for a temperature measuring device known as a thermocouple pyrometer? Low to moderate temperature applications such as refrigeration and air conditioning. Extremely low temperature applications such as cryogenics. Extremely high temperature applications such as boiler or engine exhaust temperatures. Moderate to high temperature applications such as engine cooling and lubrication. Measuring Instruments
D If a thermometer reads 80C, what is the equivalent temperature in F? 12oF 76oF 112oF 176oF Measuring Instruments
A If a thermometer reads 850F, what is the equivalent temperature in C? 454C 490C 1,472oC 1,585oC Measuring Instruments
B What statement is true concerning the vent pipes and sounding tubes associated with a vented tank?

Both the vent pipe and the sounding tube attach to and end at an opening at the top of the tank. The vent pipe attaches to and ends at an opening at the top of the tank, and the sounding tube passes through the tank top and extends almost to the tank bottom. Both the vent pipe and the sounding tube pass through the tank top and extend almost to the tank bottom. The sounding tube attaches to and ends at an opening at the top of the tank, and the vent pipe passes through the tank top and extends almost to the tank bottom. Measuring Instruments
B What statement best represents the characteristics of an innage tape and bob for the purposes of taking a vented tank sounding? The bob has a cupped end and sinks in the liquid when lowered by the tape. The bob has a pointed end and sinks in the liquid when lowered by the tape. The bob has a cupped end and floats on the surface of the liquid when lowered by the tape. The bob has a pointed end and floats on the surface of the liquid when lowered by the tape. Measuring Instruments
C What statement best represents the characteristics of an ullage tape and bob for the purposes of taking a vented tank sounding? The bob has a pointed end and sinks in the liquid when lowered by the tape. The bob has a cupped end and sinks in the liquid when lowered by the tape. The bob has a cupped end and floats on the surface of the liquid when lowered by the tape. The bob has a pointed end and floats on the surface of the liquid when lowered by the tape. Measuring Instruments
D What statement best represents the characteristics of innage and ullage tank soundings? Innage is the distance between the surface of the liquid and the top of the tank, and ullage is the distance between the surface of the liquid and the bottom of the tank. Innage is the distance between the oil/water interface and bottom of the tank, and ullage is the distance between the oil/water interface and the top of the tank. Innage is the distance between the oil/water interface and top of the tank, and ullage is the distance between the oil/water interface and the bottom of the tank. Innage is the distance between the surface of the liquid and the bottom of the tank, and ullage is the distance between the surface of the liquid and the top of the tank. Measuring Instruments
D When determining the level of a potable water hydro-pneumatic header tank fitted with a tubular sight glass, what must be taken into consideration? The sight glass must be drained, blown down, and re-filled before each reading is taken. The actual water level in the hydro pneumatic header tank is somewhat higher than the level shown in the sight glass. The actual water level in the hydro pneumatic header tank is somewhat lower than the level shown in the sight glass. The actual water level in the hydro pneumatic header tank is identical to the level shown in the sight glass. Measuring Instruments
D When determining the level of a potable water hydro-pneumatic header tank fitted with a tubular sight glass, what must be taken into consideration? The sight glass must be drained, blown down, and re-filled before each reading is taken. The actual water level in the hydro-pneumatic header tank is somewhat higher than the level
shown in the sight glass
The actual water level in the hydro-pneumatic header tank is somewhat lower than the level shown in the sight glass. The actual water level in the hydro-pneumatic header tank is identical to the level shown in the
sight glass.
Measuring Instruments
A In what application would a reflex type flat gauge glass be used? Indicating a fresh water level, where the water is clear.  Indicating a lubricating oil level, where the oil is honey colored.  Indicating a heavy fuel oil level, where the fuel is dark. ndicating a chemically treated water level, where the water is brightly colored. Measuring Instruments
C What is the operating principle upon which a bubble tube system operates in indicating liquid tank level? The air pressure required to force air bubbles into the liquid near the top of the tank is proportional to the liquid level in the tank. The air pressure required to force air bubbles into the liquid near the bottom of the tank is inversely related to the liquid level in the tank. The air pressure required to force air bubbles into the liquid near the bottom of the tank is proportional to the liquid level in the tank. The air pressure required to force air bubbles into the liquid near the top of the tank is inversely related to the liquid level in the tank. Measuring Instruments
A Which of the following measurements would be an example of total flow? cubic meters cubic meters per hour pounds per hour gallons per minute Measuring Instruments
C Which of the following measurements would be an example of flow rate? barrels meters per second cubic meters per hour gallons Measuring Instruments
C Which of the following is an example of a flow meter which has associated with it a float for flow indication purposes? A turbine type flow meter A differential pressure flow meter A variable volume flow meter (rotameter) A nutating disc flow meter Measuring Instruments
B What is the operating principle of a variable area flow meter, such as a rotameter? The float or rotor is less dense than the fluid being measured and is positioned so that the gravitational force up is balanced by the downward motion of the fluid flow. The float or rotor is more dense than the fluid being measured and is positioned so that the gravitational force down is balanced by the upward motion of the fluid flow. The float or rotor is less dense than the fluid being measured and is positioned so that the gravitational force down is balanced by the upward motion of the fluid flow. The float or rotor is more dense than the fluid being measured and is positioned so that the gravitational force up is balanced by the downward motion of the fluid flow. Measuring Instruments
C The device shown in the illustration is commonly used to __________. Illustration GS-0120 pump refrigerant generate electricity compress air pump heavy liquids Oily Water Separators
B The line labeled "E", as shown in the illustration, would be identified as the __________. Illustration GS-0175 oily bilge water outlet oily bilge water inlet processed oil outlet clean water flushing line Oily Water Separators
C Which of the valves listed for the device shown in the illustration will be open while the unit is operating in the back flush mode? Illustration GS-0153 valve "4"  valves "4" and "5" valves "4" and "14" valves "4", "5", and "14" Oily Water Separators
A In the operation of a lube oil clarifier, the position of the oil-water interface should be __________. non-existent maintained by the number of disks in the disk stack maintained by the diaphragm-type, weir control valve maintained by the ring dam Oily Water Separators
C A centrifuge will satisfactorily remove which of the listed substances from lube oil? Gasoline Diesel fuel Carbon particles Fuel oil Oily Water Separators
D When water is removed from lube oil passing through a centrifugal purifier, the water removed will __________. force the diameter of the oil column within the bowl to be narrowed be retained in the bowl displace water from the heavy phase discharge port, but of an amount less than that removed from the oil displace an equal amount of water from the bowl seal Oily Water Separators
A Of the many impurities commonly found in marine lubricating oil, which of the following CANNOT be removed by a centrifugal purifier at normal operating speeds and temperatures? Diesel fuel oil Metal particles Water Carbon particles Oily Water Separators
A What is an engine room bilge oily-water separator designed to do? Remove small amounts of oil from large amounts of water. Remove small amounts of oil from small amounts of water. Remove small amounts of water from large amounts of oil. Remove small amounts of oil from small amounts of water. Oily Water Separators
D What type of fuel oil as part of an oily-water mixture is most likely to have a density approaching that of water? Light distillate oil. Marine diesel oil. Distillate/residual fuel oil blends. Heavy residual fuel oil. Oily Water Separators
C What statement is true concerning the effect of elevating the temperature of the oily-water mixture associated with an oily-water separator? Heating the oily-water mixture decreases the viscosity of the oil and decreases the specific gravity differential between the oil and water.  Heating the oily-water mixture increases the viscosity of the oil and decreases the specific gravity differential between the oil and water. Heating the oily-water mixture decreases the viscosity of the oil and increases the specific gravity differential between the oil and water. Heating the oily-water mixture increases the viscosity of the oil and increases the specific gravity differential between the oil and water. Oily Water Separators
D What statement is true concerning the polishing coalescer filter of an oily-water separator? The coalescing filter is typically a hydrophilic filter meaning that small droplets of entrained water of the oily-water mixture coalesce on the filter and form large globules of water that sink to the bottom of the filter housing. The coalescing filter is typically an oleophilic filter meaning that small droplets of entrained oil of the oily-water mixture coalesce on the filter and form large globules of oil that sink to the bottom of the filter housing. The coalescing filter is typically a hydrophilic filter meaning that small droplets of entrained water of the oily-water mixture coalesce on the filter and form large globules of water that rise to the top of the filter housing. The coalescing filter is typically an oleophilic filter meaning that small droplets of entrained oil of the oily-water mixture coalesce on the filter and form large globules of oil that rise to the top of the filter housing. Oily Water Separators
C Referring to the illustration, note that the solenoid in line "C" is closed. The check valve in line "E" is open. The separator service pump is running. The check valve in line "G" is closed. Valve "B" is closed. Valve "D" is open. What is the operational status of the oily-water separator unit? Illustration GS-0175 The oily-water separator is in the bilge water separation processing mode with water discharging back to the bilge water holding tank with an oil content less than 15 ppm.  The oily-water separator is in the bilge water separation processing mode with water discharging overboard with an oil content less than 15 ppm. The oily-water separator is in the bilge water separation processing mode with water discharging back to the bilge water holding tank with an oil content greater than 15 ppm. The oily-water separator is in the bilge water separation processing mode with water discharging overboard with an oil content greater than 15 ppm. Oily Water Separators
D What is an engine room bilge oily-water separator designed to do? Remove small amounts of water from large amounts of oil. Remove small amounts of water from small amounts of oil. Remove small amounts of oil from small amounts of water. Remove small amounts of oil from large amounts of water. Oily Water Separators
A What statement is true with regard to the basic operating principle of gravity associated with an oily-water separator? The density of oil is less than that of water and as a result the oil droplets in an oily-water mixture will tend to rise. The density of oil is greater than that of water and as a result the oil droplets in an oily-water mixture will tend to sink. The density of oil is greater than that of water and as a result the oil droplets in an oily-water mixture will tend to rise. The density of oil is less than that of water and as a result the oil droplets in an oily-water mixture will tend to sink. Oily Water Separators
A What type of fuel oil as part of an oily-water mixture is most likely to have a density approaching that of water? Heavy residual fuel oil. Marine diesel oil. Distillate/residual fuel oil blends. Light distillate oil. Oily Water Separators
A What type of oil as part of an oily-water mixture is most likely to require heating to facilitate separation in an oily-water separator? Heavy residual fuel oil. Diesel engine lubricating oil. Marine diesel oil. Steam turbine lubricating oil. Oily Water Separators
C In order to facilitate separation of oil from an oily-water mixture in an oily-water separator, what statement is true concerning the flow pattern of the oily-water? Ideally the flow of the oily-water should be low in flow rate and high in turbulence. Ideally the flow of the oily-water should be high in flow rate and high in turbulence. Ideally the flow of the oily-water should be low in flow rate and low in turbulence. Ideally the flow of the oily-water should be high in flow rate and low in turbulence. Oily Water Separators
D What statement is true concerning the effect of elevating the temperature of the oily-water mixture associated with an oily-water separator? Heating the oily-water mixture decreases the viscosity of the oil and decreases the specific gravity differential between the oil and water. Heating the oily-water mixture increases the viscosity of the oil and increases the specific gravity differential between the oil and water. Heating the oily-water mixture increases the viscosity of the oil and decreases the specific gravity differential between the oil and water. Heating the oily-water mixture decreases the viscosity of the oil and increases the specific gravity differential between the oil and water. Oily Water Separators
A If an oily-water separator uses an inclined plate pack to facilitate separation, what statement concerning the plate pack is true? The oil droplets collect on the underside of the plates and rise when they have reached the outer edge of the plate pack. Solid particles collect on the upper side of the plates and sink when they have reached the inner edge of the plate pack. The oil droplets collect on the upper side of the plates and sink when they have reached the outer edge of the plate pack. Solid particles collect on the underside of the plates and rise when they have reached the inner edge of the plate pack. The oil droplets collect on the upper side of the plates and rise when they have reached the outer edge of the plate pack. Solid particles collect on the underside of the plates and sink when they have reached the inner edge of the plate pack. The oil droplets collect on the underside of the plates and sink when they have reached the outer edge of the plate pack. Solid particles collect on the upper side of the plates and rise when they have reached the inner edge of the plate pack. Oily Water Separators
D A typical oily-water separator has three stages of separation. Which statement represents the correct sequential order of the stages? First stage: polishing filter coalescer. Second stage: inclined plate coalescer. Third stage: gravimetric. First stage: gravimetric. Second stage: polishing filter coalescer. Third stage: inclined plate coalescer. First stage: inclined plate coalescer. Second stage: polishing filter coalescer. Third stage: gravimetric. First stage: gravimetric. Second stage: inclined plate coalescer. Third stage: polishing filter coalescer. Oily Water Separators
A What statement is true concerning the polishing coalescer filter of an oily-water separator? The coalescing filter is typically an oleophilic filter meaning that small droplets of entrained oil of the oily-water mixture coalesce on the filter and form large globules of oil that rise to the top of the filter housing. The coalescing filter is typically an oleophilic filter meaning that small droplets of entrained oil of the oily-water mixture coalesce on the filter and form large globules of oil that sink to the bottom of the filter housing. The coalescing filter is typically a hydrophilic filter meaning that small droplets of entrained water of the oily-water mixture coalesce on the filter and form large globules of water that sink to the bottom of the filter housing. The coalescing filter is typically a hydrophilic filter meaning that small droplets of entrained water of the oily-water mixture coalesce on the filter and form large globules of water that rise to the top of the filter housing. Oily Water Separators
B Suppose a steam trap's primary purpose is to insure good heat transfer of a steam-heated heat exchanger. What statement is true concerning the outcome of a steam trap failure? Steam trap failure in a fully open position would result in exceptionally good heat transfer, and steam trap failure in a full closed position would result in exceptionally poor heat transfer. Steam trap failure in either a fully open or fully closed position would both result in exceptionally poor heat transfer. Steam trap failure in a fully open position would result in exceptionally poor heat transfer, and steam trap failure in a full closed position would result in exceptionally good heat transfer. Steam trap failure in either a fully open or fully closed position would both result in exceptionally good heat transfer. Oily Water Separators
D The component labeled "A", as shown in the illustration, would be identified as the __________. Illustration GS-0175 oil content monitor probe separator vessel pressure relief valve separator vessel vacuum breaker oil/water interface level sensing probe Oily Water Separators
B The components indicated as "7" and "8" as shown in the illustration, are known as the __________. Illustration GS-0153 first stage oil separator and drip pan inlet weir and inlet baffle second stage oil separator and drip pan outlet weir and outlet baffle Oily Water Separators
C When the oily water separator, shown in the illustration, is in operation and processing clear bilge water, what should be the internal water level? Illustration GS-0153 The water level in the tank should be slightly above the upper coalescer bed "9".
 
o
The water level should be located in the lower section of the tank as controlled by flow control

valve "14".
The water level should be located in the upper section of the tank. No water level is maintained in the tank. Oily Water Separators
D The function of item "7" shown in the illustration is to __________. Illustration GS-0153 direct the flow of the oily-water mixture against the coalescer bed support the tank access panel allow the oil accumulated to exit the device, while remaining separated from the liquid prevent separated oil from mixing with the incoming bilge water Oily Water Separators
A What is the normal direction of flow through the device shown in the illustration while operating in the processing mode? Illustration GS-0153 The oily-water mixture enters through valve "5" and exits the separator through valve "14" as processed liquid. The oily-water mixture enters through valve "4" and exits as processed liquid through valve "14". The oily-water mixture enters through valve "14" and exits with the processed liquid through valve "4". The oily-water mixture enters through the pressure control valve "2" and exits with the processed liquid through valve "14". Oily Water Separators
B The line labeled "C", as shown in the illustration, would be identified as the __________. Illustration GS-0175 processed water outlet line clean water inlet line oily bilge water inlet line waste oil discharge line Oily Water Separators
D The line labeled "E", as shown in the illustration, would be identified as the __________. Illustration GS-0175 processed water outlet line clean water inlet line waste oil outlet line oily bilge water inlet line Oily Water Separators
A The line labeled "G", as shown in the illustration, would be identified as the __________. Illustration GS-0175 waste oil outlet line processed water outlet line clean water inlet line oily bilge water inlet line Oily Water Separators
D Referring to the illustration, note that the solenoid in line "C" is closed. The check valve in line "E" is open. The separator service pump is running. The check valve in line "G" is closed. Valve "B" is open. Valve "D" is closed. What is the operational status of the oily-water separator unit? Illustration GS-0175 The oily-water separator is in the bilge water separation processing mode with water discharging back to the bilge water holding tank with an oil content less than 15 ppm. The oily-water separator is in the bilge water separation processing mode with water discharging back to the bilge water holding tank with an oil content greater than 15 ppm. The oily-water separator is in the bilge water separation processing mode with water discharging overboard with an oil content greater than 15 ppm. The oily-water separator is in the bilge water separation processing mode with water discharging overboard with an oil content less than 15 ppm. Oily Water Separators
A Referring to the illustration, note that the solenoid in line "C" is closed. The check valve in line "E" is open. The separator service pump is running. The check valve in line "G" is closed. Valve "B" is closed. Valve "D" is open. What is the operational status of the oily-water separator unit? Illustration GS-0175 The oily-water separator is in the bilge water separation processing mode with water discharging back to the bilge water holding tank with an oil content greater than 15 ppm. The oily-water separator is in the bilge water separation processing mode with water discharging back to the bilge water holding tank with an oil content less than 15 ppm. The oily-water separator is in the bilge water separation processing mode with water discharging overboard with an oil content less than 15 ppm. The oily-water separator is in the bilge water separation processing mode with water discharging overboard with an oil content greater than 15 ppm. Oily Water Separators
A Referring to the illustration, note that the solenoid in line "C" is closed. The check valve in line "E" is open. The separator service pump is running. The check valve in line "G" is closed. Valve "B" is closed. Valve "D" is open. What is the operational status of the oily-water separator unit? Illustration GS-0175 The oily-water separator is in the bilge water separation processing mode with water discharging back to the bilge water holding tank with an oil content greater than 15 ppm. The oily-water separator is in the bilge water separation processing mode with water discharging back to the bilge water holding tank with an oil content less than 15 ppm. The oily-water separator is in the bilge water separation processing mode with water discharging overboard with an oil content less than 15 ppm. The oily-water separator is in the bilge water separation processing mode with water discharging overboard with an oil content greater than 15 ppm. Oily Water Separators
B If item "1" in the illustrated oily water separator indicates an abnormally deep vacuum, which of the following conditions is the most probable cause? Illustration GS-0153 Process water inlet valve, item "5", is open. Suction line inlet strainer is obstructed. No problem exists as a high vacuum should be maintained in the chamber whose vacuum is to be measured. Coalescer beds are severely fouled. Oily Water Separators
D If item "1" shown in the illustration is a compound gage indicating zero psig and the water level in the bilges is one foot high, the unit is __________. Illustration GS-0153 in the oil discharge mode processing the bilge water damaged and should not be used not turned on Oily Water Separators
D Referring to the illustration, suppose after initiating the oil discharge mode, the oily-water separator fails to come out of the oil discharge mode in a timely fashion. Cracking open the upper sampling valve reveals the presence of water exiting under a positive pressure. What is most likely the cause? Illustration GS-0175 The lower oil/water interface detection probe fails to initiate the oil discharge mode. The clean water supply solenoid fails to open, and as a result provides no discharge pressure. The oil discharge check valve fails to open, and as a result no oil actually discharges. The upper oil/water interface detection probe fails to end the oil discharge mode. Oily Water Separators
C Referring to the illustration, what would be the result if the lower oil/water interface detection probe became faulty? Illustration GS-0175 The unit would not be able to transition from ending the oil discharge mode to initiating the separation processing mode.  The unit would not be able to transition from the overboard discharge mode to the recirculation mode while in the separation processing mode. The unit would not be able to transition from ending the separation processing mode to initiating the oil discharge mode. The unit would not be able to come out of the oily-water separator idle mode and begin processing bilge water. Oily Water Separators
C Referring to the illustration, what would be the result if the upper oil/water interface detection probe became faulty? Illustration GS-0175 The unit would not be able to transition from ending the separation processing mode to initiating the oil discharge mode.
 
The unit would not be able to transition from the overboard discharge mode to the recirculation mode while in the separation processing mode. The unit would not be able to transition from ending the oil discharge mode to initiating the separation processing mode. The unit would not be able to come out of the oily-water separator idle mode and begin processing bilge water. Oily Water Separators
A The components indicated as "7" and "8" as shown in the illustration, are known as the __________. Illustration GS-0153 inlet weir and inlet baffle first stage oil separator and drip pan outlet weir and outlet baffle second stage oil separator and drip pan Oily Water Separators
C The function of item "7" shown in the illustration is to __________. Illustration GS-0153 support the tank access panel allow the oil accumulated to exit the device, while remaining separated from the liquid prevent separated oil from mixing with the incoming bilge water direct the flow of the oily-water mixture against the coalescer bed Oily Water Separators
B What is the normal direction of flow through the device shown in the illustration while operating in the processing mode? Illustration GS-0153 The oily-water mixture enters through valve "4" and exits as processed liquid through valve "14" The oily-water mixture enters through valve "5" and exits the separator through valve "14" as processed liquid. The oily-water mixture enters through the pressure control valve "2" and exits with the processed liquid through valve "14". The oily-water mixture enters through valve "14" and exits with the processed liquid through valve "4". Oily Water Separators
D The component labeled "A", as shown in the illustration, would be identified as the __________. Illustration GS-0175 oil content monitor probe separator vessel pressure relief valve separator vessel vacuum breaker oil/water interface level sensing probe Oily Water Separators
D The line labeled "E", as shown in the illustration, would be identified as the __________. Illustration GS-0175 clean water inlet line waste oil outlet line processed water outlet line oily bilge water inlet line Oily Water Separators
C Referring to the illustration, note that the solenoid in line "C" is closed. The check valve in line "E" is open. The separator service pump is running. The check valve in line "G" is closed. Valve "B" is open. Valve "D" is closed. What is the operational status of the oily-water separator unit? Illustration GS-0175 The oily-water separator is in the bilge water separation processing mode with water discharging overboard with an oil content greater than 15 ppm.
 
o
The oily-water separator is in the bilge water separation processing mode with water discharging back to the bilge water holding tank with an oil content greater than 15 ppm. The oily-water separator is in the bilge water separation processing mode with water discharging overboard with an oil content less than 15 ppm. The oily-water separator is in the bilge water separation processing mode with water discharging back to the bilge water holding tank with an oil content less than 15 ppm. Oily Water Separators
A Referring to the illustration, an oil/water separator is in the recirculation mode due to high oil content of the processed water outlet. What action may be required before the unit is capable of discharging overboard once again? Illustration GS-0175 Flushing the oil content detector with clean water. Flushing the bilges with an emulsifying agent. Flushing the bilges with a detergent. Cleaning the bilge suction strainer. Oily Water Separators
C Referring to the illustration, what would be the result if the upper oil/water interface detection probe became faulty? Illustration GS-0175 The unit would not be able to transition from ending the separation processing mode to initiating the oil discharge mode.
 
The unit would not be able to transition from the overboard discharge mode to the recirculation mode while in the separation processing mode. The unit would not be able to transition from ending the oil discharge mode to initiating the separation processing mode. The unit would not be able to come out of the oily-water separator idle mode and begin processing bilge water. Oily Water Separators
B If item "1" in the illustrated oily water separator indicates an abnormally deep vacuum, which of the following conditions is the most probable cause? Illustration GS-0153 Coalescer beds are severely fouled. Suction line inlet strainer is obstructed. Process water inlet valve, item "5", is open. No problem exists as a high vacuum should be maintained in the chamber whose vacuum is to be measured. Oily Water Separators
A Referring to the illustration, suppose the oily-water separator vessel compound gauge is showing an unusually deep vacuum for operating in the separation processing mode with the separator service pump running. The oil content is 8.3 ppm. What is most likely the cause? Illustration GS-0175 The oily-water separator bilge suction strainer is clogged. The oily-water separator vessel relief valve is leaking. The oily-water separator service pump is worn. The bilge water holding tank level is unusually high resulting in a high level alarm. Oily Water Separators
B Referring to the illustration, suppose after initiating the oil discharge mode, the oily-water separator fails to come out of the oil discharge mode in a timely fashion. Cracking open the upper sampling valve reveals the presence of water exiting under a positive pressure. What is most likely the cause? Illustration GS-0175 The oil discharge check valve fails to open, and as a result no oil actually discharges. The upper oil/water interface detection probe fails to end the oil discharge mode. The lower oil/water interface detection probe fails to initiate the oil discharge mode. The clean water supply solenoid fails to open, and as a result provides no discharge pressure. Oily Water Separators
B Referring to the illustration, suppose after initiating the oil discharge mode, the oily-water separator fails to come out of the oil discharge mode in a timely fashion. Cracking open the upper sampling valve reveals the presence of oil exiting under positive pressure. What is most likely the cause? Illustration GS-0175 The clean water supply solenoid fails to open, and as a result provides no discharge pressure. The oil discharge check valve fails to open, and as a result no oil actually discharges. The lower oil/water interface detection probe fails to initiate the oil discharge mode. The upper oil/water interface detection probe fails to end the oil discharge mode. Oily Water Separators
A Referring to the illustration, suppose while in the oil separation processing mode, the oil content detector display screen shows 17.9 ppm and the oily-water separator is discharging back to the bilge water holding tank for re-circulation. What is most likely the cause? Illustration GS-0175 The bilge water holding tank contents is excessively contaminated with oil. The oily-water separator bilge suction strainer is excessively clogged. The oily-water separator service pump is excessively worn. The bilge water holding tank level is excessively high resulting in a high level alarm. Oily Water Separators
A The best gasket material to use in cargo fuel oil lines is __________. oil-resistant sheet packing cork sheet packing unvulcanized packing sheet asbestos Pipes, Fittings, and Valves
A Piping cross-sections over 12 inches in diameter are sized by the __________. outside diameter wall thickness threaded diameter inside diameter Pipes, Fittings, and Valves
C The illustrated valve is known as a __________. Illustration GS-0056 lift gate valve butterfly lift valve swing check valve swing globe valve Pipes, Fittings, and Valves
B The valve depicted in the illustration shown is a __________. Illustration GS-0055 gate valve butterfly valve globe valve check valve Pipes, Fittings, and Valves
D Taps and dies used for threading pipe are __________. not hardened not fluted straight tapered Pipes, Fittings, and Valves
C Which of the illustrations depicts the correct procedure for applying pipe dope? Illustration GS-0046 D C B A Pipes, Fittings, and Valves
D A thread die will be easier to start if the end of the shaft to be threaded is slightly __________. center drilled peened reamed chamfered Pipes, Fittings, and Valves
C A thread chaser is a hand tool that should only be used for __________. enlarging existing threads straightening tapered threads restoring damaged threads cutting original threads Pipes, Fittings, and Valves
B Copper coil tubing is best cut with a __________. flare cutter tubing cutter pipe cutter hand hacksaw Pipes, Fittings, and Valves
D After cutting a piece of tubing to be flared, you should __________. crimp the tube end in order to slip on the fitting flare the tube before removing the burrs rough up the outside surface of the tube end with a file remove inside burrs with a reamer Pipes, Fittings, and Valves
B Which of the following descriptions should be included when identifying the length
for pipe nipples?
Standard, extra-strong, double extra-strong, and schedule 80 Close, short, long, and tank Cast, wrought, stainless, and brass Fully threaded, half threaded, long, and short Pipes, Fittings,and Valves
A The designation 'schedule 80 extra strong' refers to __________. piping wall thickness tubing bursting strength tensile strength of bolts weight of steel plate Pipes, Fittings,and Valves
C Allowances may be made for the expansion and contraction in piping by the use of expansion joints or __________. union bulkhead fittings retractable flanges bends or loops in the line unions Pipes, Fittings,and Valves
C Fittings used to close the ends of pipe are called "pipe _______". tees  closures caps  ells Pipes, Fittings,and Valves
B A pipe coupling is a fitting having __________. outside threads on both ends inside threads on both ends a left-hand twist outside threads on one end and inside threads on one end Pipes, Fittings,and Valves
A Which of the gasket types listed is typically used on high pressure steam flange joints? Spiral wound flexitallic Wire-impregnated sheet plastic High temperature neoprene Wire-impregnated rubber Pipes, Fittings,and Valves
D To properly make and fit a new gasket to a flange, you should __________. cut grooves into the flange with a chisel to ensure good gasket contact place the gasket over the flange and knock off the excess material with a lead mallet make up the flanged joint to make an impression of the flange surfaces to insure a pattern for

 proper alignment
remove excess gasket material by trimming with scissors or tin snips Pipes, Fittings,and Valves
A When replacing a gasket in a six-bolt flanged joint, in what order should the bolts be tightened? Install and tighten bolts in pairs which are opposite each other in the flange (1-4, 2-5, and 3-6). Each bolt should be installed and tightened in consecutive order in the counterclockwise direction. Each bolt should be installed and tightened in consecutive order in the clockwise direction. Install and tighten bolts 1, 3, 4, 2, 5, and 6, in that order. Pipes, Fittings,and Valves
B If you were uncertain as to what type of gasket material to install in a pipeline, you should __________. make up the joint without a gasket until you can check with the chief check the ship's plans or manufacturer's instructions turn the old gasket over and install it again leave the old gasket in and cover it with Permatex Pipes, Fittings,and Valves
D To anneal a copper gasket, you should heat the gasket __________. and let cool slowly in the air and quench it in oil and carbonize it cherry red and quench in water Pipes, Fittings,and Valves
D Which pipe listed has the largest outside diameter? A 3/4" pipe with a double extra strong wall thickness. A 3/4" pipe with an extra strong wall thickness. A 3/4" pipe with a standard wall thickness. All have the same outside diameter. Pipes, Fittings,and Valves
D Which of the listed pipe sizes is not commonly used? 3/4 inch 3/8 inch 1/2 inch 5/8 inch Pipes, Fittings,and Valves
D Tubing is sized by __________. nominal inside diameter allowed working pressure cross-section area nominal outside diameter Pipes, Fittings,and Valves
C Copper tubing is manufactured and classified as type K, L, and M. Which type would offer the greatest wall thickness for a given nominal size? Type M Type L and M have identical wall thicknesses Type K Type L Pipes, Fittings,and Valves
D A gate valve installed in a piping system should be used __________. to throttle the flow of liquid only for lube oil service only with the stem facing down in either fully closed or fully opened positions Pipes, Fittings,and Valves
D What type of valve is shown in the illustration? Illustration GS-0047 Check valve Butterfly valve Globe valve Gate valve Pipes, Fittings,and Valves
D Which of the following statements is true concerning the valve shown in the illustration. Illustration GS-0047 The valve only requires one turn of the hand wheel to fully open. The valve seats cannot be replaced or repaired. The valve is normally used to throttle the flow of liquid. The valve is a non-rising stem design. Pipes, Fittings,and Valves
C The use of a needle valve in a piping system is recommended when requiring __________. no back flow high pressure drops close regulation of flow no pressure drops Pipes, Fittings,and Valves
D The seat of a butterfly valve will most likely be constructed of __________. admiralty metal Monel stellite a resilient material Pipes, Fittings,and Valves
D To remove a hand held right-handed straight cut reamer after it has gone all the way through a hole, you should __________. work the reamer side to side to dislodge it tap the reamer out with a soft faced hammer turn the tap wrench counterclockwise, simultaneously raising the reamer turn the tap wrench clockwise, simultaneously raising the reamer Pipes, Fittings,and Valves
D The tool used for cutting external pipe threads is called a pipe __________. cutter ratchet cutter threader stock and die Pipes, Fittings,and Valves
B Before making up a flanged joint, you should __________. cut grooves in the flange face with a chisel be certain that the flanges line up squarely heat the pipeline to expand the bolt holes have a second spare gasket on hand Pipes, Fittings,and Valves
D Before disconnecting a joint in a pipeline, you should __________. have a first aid kit on hand determine the size of the gasket hang a bucket under the joint be sure no pressure exists in the line Pipes, Fittings,and Valves
B When cutting external threads on a steel pipe with a die, you should __________.
tap the die with a hammer to break up the chips continue turning until the end of the pipe has gone through the die and is flush with the die face never use a lubricant start the die at a slight angle with the work to create tapered threads Pipes, Fittings,and Valves
A The tool used to prepare copper tubing for the installation of fittings is called a __________. flaring tool spreader stretcher swaging tool Pipes, Fittings,and Valves
A Enlarging one tube end so the end of another tube of the same size will fit inside is termed __________. swaging flaring stretching belling Pipes, Fittings,and Valves
A What statement representing the primary purpose of a steam trap is true? By draining the low point of a horizontal run of steam piping, a steam trap is used primarily to keep the steam line dry and eliminate water hammer. By draining the high point of a horizontal run of steam piping, a steam trap is used primarily to keep the steam line dry and eliminate water hammer. By draining the high point of a vertical run of steam piping, a steam trap is used primarily to keep the steam line dry and eliminate water hammer. By draining the low point of a horizontal run of steam piping, a steam trap is used primarily to insure good heat transfer efficiency. Pipes, Fittings,and Valves
D In order for a steam trap to be effective in accomplishing its intended purpose, what statement is true regarding its installation? The steam trap should never be painted, but should be covered with insulation. The steam trap should be painted to reduce corrosion and should be covered with insulation. The steam trap should be painted to reduce corrosion but should never be covered with

 insulation.
The steam trap should never be painted and should never be covered with insulation. Pipes, Fittings,and Valves
D Referring to the illustrated impulse steam trap, what would be the effect of threading the control cylinder "E" downward further into the trap body? Illustration GS-0002 The clearance between the reverse taper of the control cylinder's inner wall and the periphery of the valve disk will decrease, and as a result, the pressure drop across the periphery of the valve disk will decrease. The clearance between the reverse taper of the control cylinder's inner wall and the periphery of the valve disk will decrease, and as a result, the pressure drop across the periphery of the valve disk will increase. The clearance between the reverse taper of the control cylinder's inner wall and the periphery of the valve disk will increase, and as a result, the pressure drop across the periphery of the valve disk will increase. The clearance between the reverse taper of the control cylinder's inner wall and the periphery of the valve disk will increase, and as a result, the pressure drop across the periphery of the valve disk will decrease. Pipes, Fittings,and Valves
A Referring to the illustrated impulse steam trap, what would be the effect of threading the control cylinder "E" upward out of the trap body? Illustration GS-0002 The clearance between the reverse taper of the control cylinder's inner wall and the periphery of the valve disk will decrease, and as a result, the pressure drop across the periphery of the valve disk will increase. The clearance between the reverse taper of the control cylinder's inner wall and the periphery of the valve disk will decrease, and as a result, the pressure drop across the periphery of the valve disk will decrease. The clearance between the reverse taper of the control cylinder's inner wall and the periphery of the valve disk will increase, and as a result, the pressure drop across the periphery of the valve disk will decrease. The clearance between the reverse taper of the control cylinder's inner wall and the periphery of the valve disk will increase, and as a result, the pressure drop across the periphery of the valve disk will increase. Pipes, Fittings,and Valves
A Referring to the illustrated bellows-type thermostatic steam trap, what statement is true concerning its operation? Illustration GS-0005 When the bellows comes into contact with relatively cool condensate, the vapor within the bellows condenses resulting in bellows contraction and valve opening. When the bellows comes into contact with relatively hot steam, the vapor within the bellows condenses resulting in bellows contraction and valve opening. When the bellows comes into contact with relatively cool condensate, the liquid within the bellows vaporizes resulting in bellows expansion and valve closing. When the bellows comes into contact with relatively hot steam, the liquid within the bellows vaporizes resulting in bellows contraction and valve opening. Pipes, Fittings,and Valves
D What type of steam trap is most susceptible to damage if allowed to come into contact with superheated steam? Mechanical traps relying on the principle of buoyancy. Thermodynamic traps relying on the principle of condensate undergoing a pressure drop and flashing. Thermostatic traps relying on the principle of differing expansion rates for dissimilar metals. Thermostatic traps relying on the principle of expansion/contraction of a volatile fluid. Pipes, Fittings,and Valves
B In the illustrated self-contained, internal-pilot, piston-operated temperature control valve, what statement is true concerning the pilot and main valves? Illustration GS-0045 The pilot valve is downward seating and the main valve is upward seating. The pilot valve is upward seating and the main valve is upward seating. The pilot valve is downward seating and the main valve is downward seating. The pilot valve is upward seating and the main valve is downward seating. Pipes, Fittings,and Valves
B Suppose the illustrated self-contained, internal-pilot, piston-operated temperature control valve is part of the temperature control system for a steam-heated heavy fuel oil service heater for a steam boiler. If there was an increase in demand for fuel by the boiler, what statement correctly represents how the valve would initially respond? Illustration GS-0045 The fuel oil heater fuel outlet temperature would increase, causing the remote bulb pressure to increase and the control diaphragm to flex downward and through lever action, further close the pilot valve. The fuel oil heater fuel outlet temperature would decrease, causing the remote bulb pressure to decrease and the control diaphragm to flex upward and through lever action, further open the pilot valve. The fuel oil heater fuel outlet temperature would decrease, causing the remote bulb pressure to decrease and the control diaphragm to flex downward and through lever action, further close the pilot valve. The fuel oil heater fuel outlet temperature would increase, causing the remote bulb pressure to increase and the control diaphragm to flex upward and through lever action, further open the pilot valve. Pipes, Fittings,and Valves
B How would the illustrated valve respond to a complete loss of charge from the remote bulb-to-control diaphragm power element if the valve is used as a temperature control valve for a steam-heated heavy fuel oil service heater? Illustration GS-0045 The valve would fail in the fully-closed position, resulting in a low fuel oil temperature alarm. The valve would fail in the fully-open position, resulting in a high fuel oil temperature alarm. It is not possible to predict how the valve will respond to a complete loss of charge from the power element. The valve would fail in the exact position it was in before the power element lost its complete charge, resulting in a fluctuation in fuel oil temperature as demand changes. Pipes, Fittings,and Valves
A In the illustrated self-contained, internal-pilot, piston-operated steam pressure-reducing valve, what statement is true concerning the opening and closing forces acting upon the control diaphragm? Illustration GS-0044 The spring (F) force acting on the control diaphragm is a pilot valve opening force, and the downstream pressure (J) acting on the control diaphragm is a pilot valve closing force. The spring (F) force acting on the control diaphragm is a pilot valve opening force, and the upstream pressure (C) acting on the control diaphragm is a pilot valve closing force. The spring (F) force acting on the control diaphragm is a pilot valve closing force, and the upstream pressure (C) acting on the control diaphragm is a pilot valve opening force. The spring (F) force acting on the control diaphragm is a pilot valve closing force, and the downstream pressure (J) acting on the control diaphragm is a pilot valve opening force. Pipes, Fittings,and Valves
B How would the pressure setting of the illustrated self-contained, internal-pilot, piston-operated steam pressure-reducer be reduced to a lower set point? Illustration GS-0044 The adjusting spring would need to have its compression load reduced by rotating the adjusting screw clockwise further into the adjusting spring chamber. The adjusting spring would need to have its compression load reduced by rotating the adjusting screw counter-clockwise further out of the adjusting spring chamber. The adjusting spring would need to have its compression load increased by rotating the adjusting screw counter-clockwise further out of the adjusting spring chamber. The adjusting spring would need to have its compression load increased by rotating the adjusting screw clockwise further into the adjusting spring chamber. Pipes, Fittings,and Valves
D Suppose the illustrated self-contained, internal-pilot, piston-operated temperature control valve is part of the temperature control system for a steam-heated heavy fuel oil service heater for a steam boiler. If there was a decrease in demand for fuel by the boiler, what statement correctly represents how the valve would initially respond? Illustration GS-0045 The fuel oil heater fuel outlet temperature would decrease, causing the remote bulb pressure to decrease and the control diaphragm to flex upward and through lever action, further open the pilot valve. The fuel oil heater fuel outlet temperature would increase, causing the remote bulb pressure to increase and the control diaphragm to flex upward and through lever action, further open the pilot valve. The fuel oil heater fuel outlet temperature would decrease, causing the remote bulb pressure to decrease and the control diaphragm to flex downward and through lever action, further close the pilot valve. The fuel oil heater fuel outlet temperature would increase, causing the remote bulb pressure to increase and the control diaphragm to flex downward and through lever action, further close the pilot valve. Pipes, Fittings,and Valves
A Concerning pressure-relief valves, what statement is true? No stop isolation valve may be installed between the relief valve and its source of pressure, and no stop isolation valve may be installed in the relief valve discharge piping. It is permissible to install a stop isolation valve between the relief valve and its source of pressure, but no stop isolation valve may be installed in the relief valve discharge piping. It is permissible for a stop isolation valve to be installed between the relief valve and its source of pressure, and it is permissible for a stop isolation valve to be installed in the relief valve discharge piping. No stop isolation valve may be installed between the relief valve and its source of pressure, but it is permissible for a stop isolation valve to be installed in the relief valve discharge piping. Pipes, Fittings,and Valves
C Referring to the illustrated huddling-chamber safety valve, what statement concerning the blowdown adjusting ring (B) is true? Illustration SG-0018 Lowering the blow down adjusting ring further increases the area of exposure to pressure after the valve pops and as a result, the valve blow down will decrease. Lowering the blow down adjusting ring further decreases the area of exposure to pressure after the valve pops and as a result, the valve blow down will increase. Lowering the blow down adjusting ring further decreases the area of exposure to pressure after the valve pops and as a result, the valve blow down will decrease. Lowering the blow down adjusting ring further increases the area of exposure to pressure after the valve pops and as a result, the valve blow down will increase. Pipes, Fittings,and Valves
C Concerning sentinel valves, what statement is true? The set point of the sentinel valve is usually above the maximum allowable working pressure of the system. The capacity of a sentinel valve must exceed the capacity of the pressure source. The sentinel valve's sole purpose is to warn personnel of excessive system pressure. The set point of a sentinel valve is normally set below the normal working pressure of the system. Pipes, Fittings,and Valves
A Concerning safety valves, what statement is true? Safety valves are designed to open wide when lifted by excessive pressure and only reseat when the pressure has dropped significantly. Safety valves are always set to relieve at a pressure exceeding the maximum allowable working pressure of the system. Safety valves are designed to throttle and adjust the flow rate to just keep up with the capacity
of the pressure source.
Safety valves are designed to open wide when lifted by excessive pressure and immediately
reseat when the pressure has dropped by a very small amount.
Pipes, Fittings,and Valves
A In the illustrated huddling-chamber safety valve, what statement is true concerning the opening and closing forces acting upon the disc? Illustration SG-0018 The spring force acting upward on the disc is a valve opening force, and the sensed pressure acting downward on the disc is a valve closing force. The spring force acting upward on the disc is a valve closing force, and the sensed pressure acting downward on the disc is a valve opening force. The spring force acting downward on the disc is a valve opening force, and the sensed pressure acting upward on the disc is a valve closing force. The spring force acting downward on the disc is a valve closing force, and the sensed pressure acting upward on the disc is a valve opening force. Pipes, Fittings,and Valves
C Which of the following listed valves would require "blow down" to insure proper operation and prevent damage due to repeated and rapid opening and closing? Pressure-reducing valve Pressure-relief valve Safety valve Pressure-regulating relief valve Pipes, Fittings,and Valves
B Referring to the illustrated huddling-chamber safety valve, what statement is true concerning the adjustment of blow down? Illustration SG-0018 Blow down is adjusted by rotating the release nut (A). Blow down is adjusted by rotating the adjusting ring (B). Blow down is adjusted by rotating the compression screw after first loosening the compression screw locking nut (C). Blow down is adjusted by rotating the seat bushing (G). Pipes, Fittings,and Valves
C Referring to the illustrated huddling-chamber safety valve, what statement is true concerning the adjustment of the popping pressure? Illustration SG-0018 Popping pressure is adjusted by rotating the adjusting ring (B). Popping pressure is adjusted by rotating the release nut (A). Popping pressure is adjusted by rotating the compression screw after first loosening the compression screw locking nut (C). Popping pressure is adjusted by rotating the seat bushing (G). Pipes, Fittings,and Valves
C As it pertains to safety valves, what is the definition of blow down? Blow down is the feature of a valve that allows drainage of condensate away from the disc to prevent sticking.  Blow down is the difference between the maximum allowable working pressure and the valve popping pressure. Blow down is the difference between the valve popping pressure and the valve reseating pressure. Blow down is the difference between the maximum allowable working pressure and the valve reseating pressure. Pipes, Fittings,and Valves
D Referring to the illustrated huddling-chamber safety valve, what statement concerning the blowdown adjusting ring (B) is true? Illustration SG-0018 Raising the blow down adjusting ring further decreases the area of exposure to pressure after the valve pops and as a result, the valve blow down will decrease. Raising the blow down adjusting ring further increases the area of exposure to pressure after the valve pops and as a result, the valve blow down will decrease. Raising the blow down adjusting ring further decreases the area of exposure to pressure after the valve pops and as a result, the valve blow down will increase. Raising the blow down adjusting ring further increases the area of exposure to pressure after the valve pops and as a result, the valve blow down will increase. Pipes, Fittings,and Valves
A Referring to the illustrated pneumatically operated diaphragm actuated control valve, what statement is true? Illustration GS-0051 The control valve is direct-acting and normally open (NO). The control valve is indirect-acting and normally open (NO). The control valve is direct-acting and normally closed (NC). The control valve is indirect-acting and normally closed (NC). Pipes, Fittings,and Valves
C Suppose the illustrated pneumatically operated diaphragm actuated control valve is used to control the fuel oil outlet temperature of a steam-heated heavy fuel oil heater by controlling the steam flow. What would be the result if the stem packing was over-tightened and the stem was unable to vertically move in either direction? Illustration GS-0051 The valve would fail in the fully-closed position, most likely resulting in a low fuel oil temperature alarm condition.
 
o
It is not possible to predict how the valve would respond to over-tightened valve stem packing. The valve will lose control of the fuel oil temperature with the result that the fuel temperature will fluctuate with changes in fuel demand. The valve would fail in the fully-open position, most likely resulting in a high fuel oil temperature alarm condition. Pipes, Fittings,and Valves
D Referring to the illustrated pneumatically-operated diaphragm-actuated control valve, what statement is true? Illustration GS-0051 The control valve has a single disc which is upward seating. The control valve has a single disc which is downward seating. The control valve has two discs which are both upward seating. The control valve has two discs which are both downward seating. Pipes, Fittings,and Valves
B Assuming that the flow is from left to right on the illustrated pneumatically-operated diaphragm-actuated control valve, what statement is true? Illustration GS-0051 Inlet pressure acts on the upper surface of the top disc and the lower surface of the bottom disc for the purpose of achieving hydraulic balance so that inlet pressure does not influence the valve position. Inlet pressure acts on the lower surface of the top disc and the upper surface of the bottom disc for the purpose of achieving hydraulic balance so that inlet pressure does not influence the valve position. Inlet pressure acts on the upper surface of the top disc and the upper surface of the bottom disc for the purpose of achieving a hydraulic assist to aid in valve closing. Inlet pressure acts on the lower surface of the top disc and the lower surface of the bottom disc for the purpose of achieving a hydraulic assist to aid in valve opening. Pipes, Fittings,and Valves
C In the illustrated pneumatically-operated diaphragm-actuated control valve, what statement is true concerning the opening and closing forces acting upon the control diaphragm? Illustration GS-0051 The spring force acting on the control diaphragm is a valve opening force, and the pilot pressure acting on the bottom of the control diaphragm is a valve closing force.
 
o
The spring force acting on the control diaphragm is a valve closing force, and the pilot pressure acting on the top of the control diaphragm is a valve opening force. The spring force acting on the control diaphragm is a valve opening force, and the pilot pressure acting on the top of the control diaphragm is a valve closing force. The spring force acting on the control diaphragm is a valve closing force, and the pilot pressure acting on the bottom of the control diaphragm is a valve opening force. Pipes, Fittings,and Valves
C Suppose the pilot pressure range is from 3 to 15 psig for the illustrated pneumatically operated diaphragm-actuated control valve. Assuming the control valve is trimmed for a linear response and the travel position indicator is calibrated in percentage, what would the approximate valve position with a 9 psig pilot pressure? Illustration GS-0051 25% open 33% open 50% open 75% open Pipes, Fittings,and Valves
B Suppose the pilot pressure is from 3 to 15 psig for the illustrated pneumatically operated, diaphragm actuated control valve. Assuming the control valve is trimmed for a linear response and the travel position indicator is calibrated in percentage, what would be the approximate pilot pressure if the position indicator showed the valve to be 75% open? Illustration GS-0051 4.5 psig 6.0 psig 7.5 psig 9.0 psig Pipes, Fittings,and Valves
A Suppose the pilot controller for the illustrated pneumatically operated diaphragm actuated control valve is supplied with 20 psig control air and is designed to operate the valve with a pilot pressure ranging from 3 to 15 psig. What would be the indication of a properly adjusted spring (6) by means of the adjusting nut (12)? Illustration GS-0051 The valve should indicate fully open at 3 psig and should indicate fully closed at 15 psig. The valve should indicate fully closed at 3 psig and should indicate fully open at 15 psig The valve should indicate fully open at 0 psig and should indicate fully closed at 20 psig. The valve should indicate fully closed at 0 psig and should indicate fully open at 20 psig. Pipes, Fittings,and Valves
C Suppose the illustrated pneumatically operated diaphragm actuated control valve is used to control the fuel oil outlet temperature of a steam-heated heavy fuel oil heater by controlling the steam flow. What would be the result if there was a complete loss of pilot air being delivered to the valve actuator? Illustration GS-0051 The valve would fail in the fully closed position, most likely resulting in a low fuel oil
temperature alarm condition.
The valve would fail in the exact position just before the loss of pilot air. The fuel temperature will fluctuate with changes in fuel demand. The valve would fail in the fully open position, most likely resulting in a high fuel oil
temperature alarm condition.
It is not possible to predict how the valve would respond to a loss of pilot air. Pipes, Fittings,and Valves
B As shown in the illustration, if figure "21" indicates the "TOP VIEW" of an orthographic projection, and figure "11" indicates the "FRONT VIEW", which figure would best represent the correct "RIGHT SIDE VIEW"? Illustration GS-0165 Figure "2" Figure "10" Figure "8" Figure "15" Prints And Tables
A Which of the figures shown in the illustrations depicts an orthographic projection? Illustration GS-0142 A B C D Prints And Tables
A Which of the projections represents the left side view of the object "X" in the illustration? Illustration GS-0022 A B C D Prints And Tables
B The exploded drawing shown in the illustration is intended to show the __________. Illustration GS-0025 total number of parts in the assembled component parts aligned for the correct order of reassembly disassembled component in a one point perspective view parts without using hidden lines Prints And Tables
D Of the views labeled "1", "2", "3", and "4", select the one that correctly represents the right side view of the unnumbered object in the illustration. Illustration GS-0003 1 2 3 4 Prints And Tables
A In the illustration shown, what is the proper description of the hole represented by "C"? Illustration GS-0015 Counter bored Countersunk Counter drilled Spot faced Prints And Tables
B In the illustration, line "J" is used to depict a __________. Illustration GS-0006 hidden line cutting plane line outline centerline Prints And Tables
A In the illustration, line "C" is a __________. Illustration GS-0006 dimension line leader line cutting plane line phantom line Prints And Tables
A How many hidden lines are shown in the right side (end) view of the drawing illustrated? Illustration GS-0021 None Two Four Six Prints And Tables
A Which of the conditions listed does the blueprint symbol shown in the illustration represent? Illustration GS-0028 All surfaces are to be machine finished. A groove must be machined at the points designated. The thread form to be machined on the bolt. The surface should be finished with a welded overlay. Prints And Tables
A In the illustration, line "C" is a __________. Illustration GS-0006 dimension line leader line cutting plane line phantom line Prints And Tables
A In the illustration, line "D" is a/an __________. Illustration GS-0006 hidden line sectioning line outline phantom line Prints And Tables
A In the figure shown in the illustration, the standard blueprint symbols above the letters "A", "B", and "C" indicate __________. Illustration GS-0036 the use of internal threads hole tolerance finished diameter interference fit Prints And Tables
B A 'centerline' depicted in a drawing or blueprint is represented by which of the figures shown in the illustration? Illustration GS-0031 A E D C Prints And Tables
B A 'centerline' depicted in a drawing or blueprint is represented by which of the figures shown in the illustration? Illustration GS-0031 A E C D Prints And Tables
C In the illustration shown, an efficient seal is maintained between the suction cover and the volute by __________. Illustration GS-0012 good metal-to-metal contact sealant between the two parts an asbestos gasket compressing the packing rings Prints And Tables
C Which of the speeds listed represents the synchronous speed rating of the lube oil pump motor shown in the illustration? Illustration GS-0011 1,000 RPM 1,150 RPM 1,200 RPM 1,250 RPM Prints And Tables
D What is the length of the stud used to secure the packing gland shown in the illustration? Illustration GS-0012 1 inch 1 1/4 inches 1 1/2 inches 2 1/2 inches Prints And Tables
D What is the distance between the center of the discharge outlet and the top of the motor illustrated? Illustration GS-0011 34 5/8 inches 35 inches 35 5/8 inches 36 inches Prints And Tables
D In the pump shown in the illustration, what is the distance from the bottom of the inlet to the bottom end of the motor shaft? Illustration GS-0011 45 1/4 inches 45 5/16 inches 53 5/8 inches 57 5/8 inches Prints And Tables
C The working depth of the gear illustrated is represented by __________. Illustration GS-0111 C I A B Prints And Tables
D The term, whole depth of the gear, shown in the illustration, is equal to __________. Illustration GS-0111 A + D B + D C + A C + D Prints And Tables
A Which letter represents the gear tooth working depth of the gear set illustrated? Illustration GS-0111 A B C D Prints And Tables
A The dimension of the sensing gap in the left hand limit sensor assembly shown in the illustration is __________. Illustration GS-0010 1/8 inch 1/4 inch 3/8 inch 1/2 inch Prints And Tables
B The shaft shown in the illustration has an overall length of 42 inches in addition to the following dimensions of "A" = 8", "B" = 8", "C" = 10", and "D"=8 3/16" The tapered length "X" is __________. Illustration GS-0133 6.375 inches 7.812 inches 8.185 inches 8.312 inches Prints And Tables
A The physical feature indicated for each of the smallest diameter ends of the device illustrated is that they are __________. Illustration GS-0008 threaded smooth surfaced with opposing machined flats smoothed surfaced only threaded with opposing machined flats Prints And Tables
A Which of the following statements is correct regarding the device shown in the illustration? Illustration GS-0008 The areas dimensioned 0.64 in length are flats on the shaft. The areas dimensioned 0.64 in length are steps in the shaft diameter. If the piece is symmetrical about the 3/16 hole, the threaded ends have longitudinal tolerance dimensions of 0.789 inch to 0.825 inch. All the 0.03 under cuts must be taken into account when adjusting lengths to meet the specified tolerances. Prints And Tables
A Figure "B", shown in the illustration, is dimensioned to indicate a/an __________. Illustration GS-0019 interference fit clearance of .005 inch running fit tolerance of .005 inch Prints And Tables
A The illustration shown represents a blueprint of a metal __________. Illustration GS-0028 rod with a conventional break tube with a broken out section pipe with a missing center section bar with a sawn out section Prints And Tables
A The letters 'NPT' used in the notation 1/8-27 NPT as shown in the illustration, indicates the __________. Illustration GS-0010 thread series thread profile class of finish class of fit Prints And Tables
B In the illustration shown, what is the distance indicated by dimension "I"? Illustration GS-0001 1 1/2 inches 1 3/4 inches 1 7/8 inches 2 inches Prints And Tables
B The illustration is drawn to a scale of 3/8 inch = 1 inch. What is the full size dimension of "X", if the scale lengths for "E" = 5/8", "F" = 1 3/8", "G" = 2 1/8", and "H" = 5 3/4"? Illustration GS-0007 1.625 inches 4.333 inches 6.094 inches 15.333 inches Prints And Tables
B Using the information in the illustration shown, the tail of the welding symbol will __________. Illustration GS-0030
designate the type of weldment designate the welding specifications specify the size of weldment specify the direction of welding Prints And Tables
A Which of the following propulsor types represents the proper terminology for a Kort nozzle? Ducted propeller Vane wheel Cycloidal propeller Tandem propellers Propellers / Shafting Systems
A Which of the following propulsor types does not require the use of a separate rudder for steerage? Cycloidal propellers. Contra-rotating propellers. Tandem propellers. Conventional fixed-pitch propeller. Propellers / Shafting Systems
D Which of the following propulsor types represents the proper terminology for a Voith Schneider drive? Ducted propeller Tandem propellers Vane wheel Cycloidal propeller Propellers / Shafting Systems
A Which of the following propulsor types represents the proper terminology for a screw propeller of the conventional design? Fixed pitch propeller Cycloidal propeller Detachable-blade (built-up) propeller Controllable-pitch propeller Propellers / Shafting Systems
C When an electricity generating plant features shaft-driven generators, what type of propulsor is generally used for main propulsion? Tandem propellers Detachable-blade (built-up) propeller Controllable-pitch propeller Fixed-pitch propeller Propellers / Shafting Systems
B Which of the following propulsor types would be used with unidirectional propulsion shafting rotation? Fixed-pitch propeller Controllable-pitch propeller Tandem propellers Detachable-blade (built-up) propeller Propellers / Shafting Systems
D What type of propeller consists of a flat disc set flush with the under surface of the vessel's hull with a number of vertical, rudder like blades projecting from it? Contra-rotating propeller Tandem propeller Helicoidal propeller Cycloidal propeller Propellers / Shafting Systems
A Which of the following propulsor types represents the proper terminology for a Z-drive? Azimuthing propulsor Jet drive Cycloidal propeller Azipod propulsor Propellers / Shafting Systems
C Which of the following propulsor types represents the proper terminology for electric propulsion where the drive motors are outside the ship's hull? Jet drive Azimuthing propulsor Azipod propulsor Cycloidal propeller Propellers / Shafting Systems
D Concerning the operating mechanism of a controllable-pitch propeller, what statement is true? If the hydraulic actuator is outboard, a mechanical pull-push rod is located within the propeller shaft. If the hydraulic actuator is inboard, hydraulic oil pipes are located within the propeller shaft. If the hydraulic actuator is inboard or outboard, the blade rotating mechanism is actuated by a mechanical pull-push rod located within the propeller shaft. If the hydraulic actuator is inboard or outboard, hydraulic oil pipes are located within the propeller shaft in either case. If the hydraulic actuator is inboard, a mechanical pull-push rod is located within the propeller shaft. If the hydraulic actuator is outboard, hydraulic oil pipes are located within the propeller shaft. Propellers / Shafting Systems
B If a main propulsion shafting arrangement is such that no strut or strut bearing is required, what is an alternative name given to the propeller shaft, which is the section of shafting that the propeller is attached to? Line shaft Tail shaft Thrust shaft Head shaft Propellers / Shafting Systems
D What type of bearing is most generally used as an independent main thrust block on merchant ships? Split-half journal type bearing. Plain thrust bearing. Single piece bushing. Pivoted-shoe thrust bearing. Propellers / Shafting Systems
D What statement is true concerning the lubrication of line shaft bearings? Line shaft bearings are generally lubricated by wick lubrication. Line shaft bearing are generally lubricated by force-feed lubrication. Line shaft bearings are generally lubricated by gravity feed lubrication. Line shaft bearings are generally lubricated by oiling rings or discs Propellers / Shafting Systems
A What statement is true concerning the arrangement of line shaft bearing housings? Line shaft bearing housings are typically split half pedestal type bearing housings. Line shaft bearing housings are typically split half flange type bearing housings. Line shaft bearing housings are typically single-piece flange type bearing housings. Line shaft bearing housings are typically single-piece pedestal type bearing housings. Propellers / Shafting Systems
A What statement is true concerning the ability of a line shaft bearing to adapt to shaft misalignment as the ship's hull flexes? Some line shaft bearings may have only a bottom half bearing shell, which allows for deflection upwards only. Other line shaft bearings may be spherically-seated self-aligning bearings or conventional non-aligning type bearings. All line shaft bearings have only a top half bearing shell, which allows for deflection downwards only. As such no provision is made for allowing for deflection in other directions. All line shaft bearings have only a bottom half bearing shell, which allows for deflection upwards only. As such no provision is made for allowing for deflection in other directions. Some line shaft bearings may have only a top half bearing shell, which allows for deflection downwards only. Other line shaft bearings may be spherically-seated self-aligning bearings or conventional non-aligning type bearings. Propellers / Shafting Systems
A What statement is true concerning the purpose of an independent main thrust bearing where used? The main purpose of the main thrust bearing is to absorb axial thrust and to transmit the axial thrust developed by the propeller to the ship's hull. The main purpose of the main thrust bearing is to absorb axial thrust and maintain the shaft in proper axial alignment. The main purpose of the main thrust bearing is to absorb radial thrust and maintain the shaft in proper radial alignment. The main purpose of the main thrust bearing is to absorb radial thrust and to transmit the radial thrust developed by the propeller to the ship's hull. Propellers / Shafting Systems
D Which line shaft bearing is most likely to have both upper and lower half bearing shells on merchant ships? The intermediate line shaft bearing. The forward most line shaft bearing. All line shaft bearings have only a lower bearing shell. The aftermost line shaft bearing. Propellers / Shafting Systems
C Concerning the arrangements of a disk-oiled line shaft bearing, what statement is true? The disk is clamped to the shaft with the lowermost part immersed in oil, and the distribution of the oil to the bearing is by the action of an oil wick.
 
o
The disk fits loosely on the shaft with the lowermost part immersed in oil, and the distribution of the oil to the bearing is by wick action The disk is clamped to the shaft with the lowermost part immersed in oil, and the distribution of the oil to the bearing is by the action of an oil scraper. The disk fits loosely on the shaft with the lowermost part immersed in oil, and the distribution of the oil to the bearing is similar to the action of oiling rings. Propellers / Shafting Systems
D What statement is true with respect to the back of a propeller blade? The back of the propeller blade is the side of the blade which faces upstream during ahead motion and is the side of the blade known as the pressure side. The back of the propeller blade is the side of the blade which faces downstream during ahead motion and is the side of the blade known as the pressure side. The back of the propeller blade is the side of the blade which faces downstream during ahead motion and is the side of the blade known as the suction side. The back of the propeller blade is the side of the blade which faces upstream during ahead motion and is the side of the blade known as the suction side. Propellers / Shafting Systems
D What is meant by the term "left-handed" propeller? A "left-handed" propeller is a propeller located on the starboard side and which can rotate in either direction. A "left-handed" propeller is a propeller located on the port side and which can rotate in either direction. A "left-handed" propeller is a propeller which rotates in the counter-clockwise direction when viewed from ahead. A "left-handed" propeller is a propeller which rotates in the counter-clockwise direction when viewed from astern. Propellers / Shafting Systems
B What is meant by the term "right-handed" propeller? A "right-handed" propeller is a propeller located on the port side and which can rotate in either direction. A "right-handed" propeller is a propeller which rotates in the clockwise direction when viewed from astern. A "right-handed" propeller is a propeller located on the starboard side and which can rotate in either direction. A "right-handed" propeller is a propeller which rotates in the clockwise direction when viewed from ahead. Propellers / Shafting Systems
D What statement is true with respect to the pressure side of a propeller blade? The pressure side of the propeller blade is the side of the blade which faces downstream during ahead motion and is also known as the back of the blade. The pressure side of the propeller blade is the side of the blade which faces upstream during ahead motion and is also known as the back of the blade. The pressure side of the propeller blade is the side of the blade which faces upstream during ahead motion and is also known as the face of the blade. The pressure side of the propeller blade is the side of the blade which faces downstream during ahead motion and is also known as the face of the blade. Propellers / Shafting Systems
C Concerning transverse fixed tunnel thrusters, what statement is true? Transverse fixed tunnel thrusters are oriented fore-to-aft, usually located at the stern of a vessel, and used for docking, undocking, and low-speed maneuvering.
 
Transverse fixed tunnel thrusters are oriented athwartships, usually located at the bow of a vessel, and used to supplement main propulsion for higher sustained speeds. Transverse fixed tunnel thrusters are oriented athwartships, usually located at the bow of a vessel, and used for docking, undocking, and low-speed maneuvering. Transverse fixed tunnel thrusters are oriented fore-to-aft, usually located at the stern of a vessel, and used to supplement main propulsion for higher sustained speeds. Propellers / Shafting Systems
C Which set of operating conditions would be most problematic in terms of the deterioration of the insulation resistance of the drive motor of an electric motor driven transverse tunnel bow thruster? Frequently used thrusters where the bow thruster machinery compartment is particularly cold.
 
Frequently used thrusters where the bow thruster machinery compartment is particularly warm. Infrequently used thrusters where the bow thruster machinery compartment is particularly cold. Infrequently used thrusters where the bow thruster machinery compartment is particularly warm. Propellers / Shafting Systems
D Concerning steerable internal duct thrusters, what statement is true? The thrust direction of the steerable internal duct thruster is determined by the direction of rotation of the pump. The thrust direction of the steerable internal duct thruster is determined by reversing the pitch angle of the pump impeller. The thrust direction of the steerable internal duct thruster is determined by the orientation of the pump inlet guide vanes. The thrust direction of the steerable internal duct thruster is determined by the orientation of the water discharge vectoring ring. Propellers / Shafting Systems
B With respect to the vectoring ring of a steerable internal duct thruster, what statement represents the operating principle of the vectoring ring? The vectoring ring is used to control the orientation of the inlet guide vanes to the pump inlet. The vectoring ring is used to control the orientation of the deflector vanes of the pump discharge. The vectoring ring is used to control the speed and direction of rotation of the pump. The vectoring ring is used to control the orientation of the vanes on the pump impeller. Propellers / Shafting Systems
A What statement represents the fundamental difference between an azimuthing thruster and a podded propulsor? With an azimuthing thruster the prime mover is located inside the hull, and with a podded propulsor the prime mover is located outside the hull. With an azimuthing thruster the prime mover is located outside the hull, and with a podded propulsor the prime mover is located inside the hull. With an azimuthing thruster the thruster is not steerable, and with a podded propulsor the propulsor is steerable. With an azimuthing thruster the thruster is steerable, and with a podded propulsor the propulsor is not steerable. Propellers / Shafting Systems
D With respect to a "pusher" type azimuthing thruster, what statement is true? With an azimuthing angle of 0, the azimuthing thruster's propeller is directly abaft of the gear unit, but the gear unit is in the wake of the azimuthing thruster's propeller. With an azimuthing angle of 0, the gear unit is directly abaft of and in the wake of the azimuthing thruster's propeller. With an azimuthing angle of 0, the gear unit is directly abaft of the azimuthing thruster's propeller, but the azimuthing thruster's propeller is in the wake of the gear unit. With an azimuthing angle of 0, the azimuthing thruster's propeller is directly abaft of and in the wake of the gear unit. Propellers / Shafting Systems
A With respect to a "tractor" type azimuthing thruster, what statement is true? With an azimuthing angle of 0, the gear unit is directly abaft of and in the wake of the azimuthing thruster's propeller. With an azimuthing angle of 0, the azimuthing thruster's propeller is directly abaft of and in the wake of the gear unit. With an azimuthing angle of 0, the gear unit is directly abaft of the azimuthing thruster's propeller, but the azimuthing thruster's propeller is in the wake of the gear unit. With an azimuthing angle of 0, the azimuthing thruster's propeller is directly abaft of the gear unit, but the gear unit is in the wake of the azimuthing thruster's propeller. Propellers / Shafting Systems
C By what means is electric current conveyed to the electric drive motor of a podded propulsor? Current is conveyed from the source to a set of stationary brushes, then through a single rotating slip ring and then on to the motor windings.
 
Current is conveyed from the source to a set of stationary slip rings, then through a set of rotating brushes and then on to the motor windings. Current is conveyed from the source to a set of stationary brushes, then through a set of rotating slip rings and then on to the motor windings. Current is conveyed from the source to the stator of a synchronous transmitter, and by synchro action to the rotor of a synchronous receiver. Propellers / Shafting Systems
D What type of propulsor is typically used in electric motor driven, transverse, tunnel bow thrusters to limit the starting current of the single speed drive motor? Fixed-pitch propeller Detachable-blade (built-up) propeller Cycloidal propeller Controllable-pitch propeller Propellers / Shafting Systems
B What is the primary advantage of transverse bow and stern tunnel thrusters when installed on ships? They provide increased overall propulsive reverse thrust. They provide increased maneuverability at low ship speeds. They provide increased overall propulsive forward thrust. They provide increased maneuverability at high ship speeds. Propellers / Shafting Systems
C The gears used for virtually all marine propulsion reduction gear sets are of what type? Single spur gears Single helical gears Double helical gears Double bevel gears Propellers / Shafting Systems
D Of the following propulsion modes, which one would operate with a geared-drive featuring a double reduction? Slow speed diesel Medium speed diesel High speed diesel Gas turbine Propellers / Shafting Systems
A An 8" diameter wheel is driving a 20" diameter wheel via a pair of belts. The power input is supplied by a 5 HP motor rotating the driving wheel at 300 RPM. If the efficiency of the transmission is 80%, what RPM and torque is delivered to the driven wheel? 120 RPM at 4 HP 160 RPM at 4 HP 220 RPM at 4.5 HP 220 RPM at 4.8 HP Propellers / Shafting Systems
B Of the following propulsion modes, which one would operate with a geared-drive featuring a single reduction? Slow speed diesel Medium speed diesel Steam turbine Gas turbine Propellers / Shafting Systems
A What is an example of an epicyclic gear? Planetary gear Articulated gear Nested gear Locked train gear Propellers / Shafting Systems
A For a parallel axis single reduction gear, what statement is true? The drive pinion is the smaller of the two gears and rotates at a relatively high speed. The driven gear is the larger of the two gears and rotates at a relatively low speed. The drive pinion is the smaller of the two gears and rotates at a relatively low speed. The driven gear is the larger of the two gears and rotates at a relatively high speed. The drive pinion is the larger of the two gears and rotates at a relatively high speed. The driven gear is the smaller of the two gears and rotates at a relatively low speed. The drive pinion is the larger of the two gears and rotates at a relatively low speed. The driven gear is the smaller of the two gears and rotates at a relatively high speed. Propellers / Shafting Systems
D Which of the listed reduction gear sets has the input and output shafts in-line with one another? Parallel axis gearing Bevel gearing Worm gearing Epicyclic gearing Propellers / Shafting Systems
B Which of the following couplings or clutches would be able to prevent the transmission of torsional vibrations from an engine to a reduction gear? Inflatable tire-type pneumatic clutch Hydraulic fluid-type clutch Multiple disk friction clutch Solid coupling Propellers / Shafting Systems
D Which of the following couplings or clutches allows, within limits, a certain degree of slip? Inflatable tire type clutch Flexible coupling Multiple disk friction clutch Electro-magnetic clutch Propellers / Shafting Systems
A Concerning main propulsion reduction gears, what statement is true? The reduction gear allows the prime mover to rotate efficiently at relatively high speed and low torque and allows the propeller to rotate efficiently at relatively low speed and high torque. The reduction gear allows the prime mover to rotate efficiently at relatively high speed and high torque and allows the propeller to rotate efficiently at relatively low speed and low torque. The reduction gear allows the prime mover to rotate efficiently at relatively low speed and low torque and allows the propeller to rotate efficiently at relatively high speed and high torque. The reduction gear allows the prime mover to rotate efficiently at relatively low speed and high torque and allows the propeller to rotate efficiently at relatively high speed and low torque. Propellers / Shafting Systems
C What is a shipboard application for a worm gear drive? Main propulsion reduction gear. Turbo-generator reduction gear. Main engine turning gear. Auxiliary power take-off gear. Propellers / Shafting Systems
C Which of the following propulsor types represents the proper terminology for a Voith Schneider drive? Tandem propellers Ducted propeller Cycloidal propeller Vane wheel Propellers / Shafting Systems
A When an electricity generating plant features shaft-driven generators, what type of propulsor is generally used for main propulsion? Controllable-pitch propeller Tandem propellers Fixed-pitch propeller Detachable-blade (built-up) propeller Propellers / Shafting Systems
B What type of propeller consists of a flat disc set flush with the under surface of the vessel's hull with a number of vertical, rudder-like blades projecting from it? Helicoidal propeller Cycloidal propeller Contra-rotating propeller Tandem propeller Propellers / Shafting Systems
B Which of the following propulsor types represents the proper terminology for electric propulsion where the drive motors are outside the ship's hull? Jet drive Azipod propulsor Cycloidal propeller Azimuthing propulsor Propellers / Shafting Systems
B Which of the following propulsor types does not require the use of a separate rudder for steerage? Contra-rotating propellers. Cycloidal propellers. Conventional fixed-pitch propeller. Tandem propellers. Propellers / Shafting Systems
C Concerning steerable internal duct thrusters, what statement is true? The thrust direction of the steerable internal duct thruster is determined by the orientation of the pump inlet guide vanes.
 
The thrust direction of the steerable internal duct thruster is determined by reversing the pitch angle of the pump impeller. The thrust direction of the steerable internal duct thruster is determined by the orientation of the water discharge vectoring ring. The thrust direction of the steerable internal duct thruster is determined by the direction of rotation of the pump. Propellers / Shafting Systems
D What statement represents the fundamental difference between an azimuthing thruster and a podded propulsor? With an azimuthing thruster the thruster is not steerable, and with a podded propulsor the propulsor is steerable. With an azimuthing thruster the thruster is steerable, and with a podded propulsor the propulsor is not steerable. With an azimuthing thruster the prime mover is located outside the hull, and with a podded propulsor the prime mover is located inside the hull. With an azimuthing thruster the prime mover is located inside the hull, and with a podded propulsor the prime mover is located outside the hull. Propellers / Shafting Systems
B With respect to a "tractor" type azimuthing thruster, what statement is true? With an azimuthing angle of 0, the gear unit is directly abaft of the azimuthing thruster's propeller, but the azimuthing thruster's propeller is in the wake of the gear unit. With an azimuthing angle of 0, the gear unit is directly abaft of and in the wake of the azimuthing thruster's propeller. With an azimuthing angle of 0, the azimuthing thruster's propeller is directly abaft of the gear unit, but the gear unit is in the wake of the azimuthing thruster's propeller. With an azimuthing angle of 0, the azimuthing thruster's propeller is directly abaft of and in the wake of the gear unit. Propellers / Shafting Systems
C What type of propulsor is typically used in electric motor driven, transverse, tunnel bow thrusters to limit the starting current of the single speed drive motor? Cycloidal propeller Detachable-blade (built-up) propeller Controllable-pitch propeller Fixed-pitch propeller Propellers / Shafting Systems
D Which set of operating conditions would be most problematic in terms of the deterioration of the insulation resistance of the drive motor of an electric motor driven transverse tunnel bow thruster? Frequently used thrusters where the bow thruster machinery compartment is particularly warm. Frequently used thrusters where the bow thruster machinery compartment is particularly cold. Infrequently used thrusters where the bow thruster machinery compartment is particularly warm. Infrequently used thrusters where the bow thruster machinery compartment is particularly cold. Propellers / Shafting Systems
B Of the following propulsion modes, which one would operate with a geared-drive featuring a single reduction? Slow speed diesel Medium speed diesel Steam turbine Gas turbine Propellers / Shafting Systems
A For a parallel axis single reduction gear, what statement is true? The drive pinion is the smaller of the two gears and rotates at a relatively high speed. The driven gear is the larger of the two gears and rotates at a relatively low speed. The drive pinion is the smaller of the two gears and rotates at a relatively low speed. The driven gear is the larger of the two gears and rotates at a relatively high speed. The drive pinion is the larger of the two gears and rotates at a relatively high speed. The driven gear is the smaller of the two gears and rotates at a relatively low speed. The drive pinion is the larger of the two gears and rotates at a relatively low speed. The driven gear is the smaller of the two gears and rotates at a relatively high speed. Propellers / Shafting Systems
B Which of the following couplings or clutches would be able to prevent the transmission of torsional vibrations from an engine to a reduction gear? Inflatable tire-type pneumatic clutch Hydraulic fluid-type clutch Multiple disk friction clutch Solid coupling Propellers / Shafting Systems
A Concerning main propulsion reduction gears, what statement is true? The reduction gear allows the prime mover to rotate efficiently at relatively high speed and low torque and allows the propeller to rotate efficiently at relatively low speed and high torque. The reduction gear allows the prime mover to rotate efficiently at relatively high speed and high torque and allows the propeller to rotate efficiently at relatively low speed and low torque. The reduction gear allows the prime mover to rotate efficiently at relatively low speed and low torque and allows the propeller to rotate efficiently at relatively high speed and high torque. The reduction gear allows the prime mover to rotate efficiently at relatively low speed and high torque and allows the propeller to rotate efficiently at relatively high speed and low torque. Propellers / Shafting Systems
D Of the following propulsion modes, which one would operate with a geared-drive featuring a double reduction? Slow speed diesel Medium speed diesel High speed diesel Gas turbine Propellers / Shafting Systems
D If a main propulsion shafting arrangement is such that a strut and strut bearing is required, what is the name of the section of shafting that passes through the hull penetration to the closest water-tight bulkhead? Tail or propeller shaft Line shaft Thrust shaft Stern tube shaft Propellers / Shafting Systems
A What statement is true concerning the arrangement of line shaft bearing housings? Line shaft bearing housings are typically split half pedestal type bearing housings. Line shaft bearing housings are typically single-piece pedestal type bearing housings. Line shaft bearing housings are typically single-piece flange type bearing housings. Line shaft bearing housings are typically split half flange type bearing housings. Propellers / Shafting Systems
A What statement is true concerning the purpose of an independent main thrust bearing where used? The main purpose of the main thrust bearing is to absorb axial thrust and to transmit the axial thrust developed by the propeller to the ship's hull. The main purpose of the main thrust bearing is to absorb axial thrust and maintain the shaft in proper axial alignment. The main purpose of the main thrust bearing is to absorb radial thrust and maintain the shaft in proper radial alignment. The main purpose of the main thrust bearing is to absorb radial thrust and to transmit the radial thrust developed by the propeller to the ship's hull. Propellers / Shafting Systems
C Concerning the proper lubrication of a ring-oiled line shaft bearing, what statement is true? The oil level should be maintained high enough so that some oil is seen exiting the bearing along the shaft.
 
The oil level should be high enough so that the oiling rings dip into the oil, but the rings must not be allowed to freely rotate with the shaft. The oil level should be high enough so that the oiling rings dip into the oil, and the rings must freely rotate with the shaft. The oil level should be maintained high enough so that the entire bearing is continuously flooded. Propellers / Shafting Systems
D What type of bearing is most generally used as an independent main thrust block on merchant ships? Split-half journal type bearing. Plain thrust bearing. Single piece bushing. Pivoted-shoe thrust bearing. Propellers / Shafting Systems
C The property of a fuel oil which is a measurement of its available energy, is known as its __________. cetane index cetane number heating value viscosity index Properties Of Fuel 
D Which of the listed characteristics of fuel oil establishes the danger point as far as transferring, pumping, and firing procedures are concerned? Viscosity Fire point Specific gravity Flash point Properties Of Fuel 
B Which characteristic of fuel oil is the most significant when determining the temperature to which the fuel oil must be heated for proper atomization? Flash point Viscosity Pour point Specific gravity Properties Of Fuel 
B The BTU value of fuel oil is determined by a/an __________. viscosimeter calorimeter open cup test hydrometer Properties Of Fuel 
A Which combustible element in fuel oil is considered a significant and major source of air pollution? Sulfur Vanadium Nitrogen Hydrogen Properties Of Fuel 
D When heated, fuel oil will __________. have a higher specific heat  increase in specific gravity increase in viscosity  expand in volume Properties Of Fuel 
B The main reason for having a low suction line on the fuel oil service or settling tanks is to __________. prevent loss of suction during rough weather facilitate water removal decrease suction head on the pump increase the amount of fuel available for use Properties Of Fuel 
A Which of the following terms is used to identify the pressure of a liquid entering a centrifugal pump? Suction head Pump head Discharge head Total head Pumps, Fans, and Blowers
A The shaft sleeve for the pump illustrated is identified by the item numbered as
__________. Illustration GS-0143
14 17 27 68 Pumps, Fans, and Blowers
D A centrifugal bilge pump requires priming __________. o initially unload the pump by having its head pressure equal to discharge pressure in order to overcome the potential energy of water in the discharge line primarily to lubricate the shaft seals due to the inability of this type of pump to lift water to cover the suction (eye) of the impeller Pumps, Fans, and Blowers
D The simplest method to use for determining if a centrifugal pump is operating as designed, is to __________. closely observe the pump discharge temperature momentarily close off the suction valve, and watch for a rise in pressure use a clamp on ammeter and compare the readings to past records close off the discharge valve, and watch for a rise in pressure Pumps, Fans, and Blowers
A The pressure of a liquid leaving the pump can be referred to as the __________. discharge head total head suction head net positive suction head Pumps, Fans, and Blowers
C Which of the following statements is true concerning centrifugal pumps? They are particularly suited for pumping high viscosity fluids. They are always mounted in a horizontal position. The flow of liquid is developed by imparting energy due to the rotation of an impeller. They are started with the discharge valve opened. Pumps, Fans, and Blowers
D A pump is defined as a device that __________. produces pressure creates a vacuum to move a liquid in all installations is to develop a pressure differential imparts energy to a fluid to move it from point "A" to point "B" Pumps, Fans, and Blowers
B The basic function of the centrifugal pump impeller is to __________. separate air from the liquid being pumped directly increase the velocity of the liquid being pumped directly increase the pressure of the liquid being pumped convert the potential energy of the liquid to kinetic energy Pumps, Fans, and Blowers
B The function of seal cages, or lantern rings installed in the centrifugal pump stuffing boxes, is to __________. lubricate the packing distribute the sealing liquid within the stuffing box seal air from entering along the shaft cool the shaft Pumps, Fans, and Blowers
C Air leakage between the shaft and stuffing box packing in a centrifugal pump is prevented by __________. lantern rings between the packing rings a compressed packing gland a liquid seal the stuffing box gland Pumps, Fans, and Blowers
C Permanent centrifugal pump shaft damage due to erosion, corrosion, and wear at the stuffing box is usually prevented by __________. wearing rings internally flooded lantern rings renewable sleeves a hardened sprayed metal coating Pumps, Fans, and Blowers
D What should be done if localized scoring is discovered on a pump shaft sleeve during routine maintenance inspection? Reassemble the pump and provide more water leak off for lubrication. Reassemble the pump and set the governor to obtain a slower speed. Check for parallel alignment of the sleeve radial face to the sleeve bore. Correct the cause of scoring and install a new shaft sleeve. Pumps, Fans, and Blowers
D To prevent overheating and scoring of the shaft after repacking the stuffing box, which of the following procedures should be carried out? Operating the pump slowly and applying oil freely to the shaft until the packing is properly seated. Tightening the gland in all the way and then backing it off slightly. Lubricate the lantern ring with cylinder oil before installing new turns of packing. Tighten the packing in small increments while the pump is operating. Pumps, Fans, and Blowers
B A centrifugal pump gradually develops insufficient discharge pressure. What corrective action is required? Throttle in on the discharge valve. Replace the wearing rings. Replace the lantern rings. Throttle in on the suction valve. Pumps, Fans, and Blowers
B When repacking a stuffing box fitted with a lantern ring, which of the following precautions should be observed? Be certain that all packing is fitted loosely to the shaft. Replace all of the packing rings. For good lubrication, apply a fine grade lapping compound between the shaft and packing. Block off the sealing water connection. Pumps, Fans, and Blowers
A When renewing spiral packing in a centrifugal pump stuffing box, after the packing is firmly seated, the packing gland nuts should be __________. loosened, and then retightened with the pump running under normal conditions loosened until the gland clears the stuffing box left in that position tightened an additional 10% to compress the packing Pumps, Fans, and Blowers
C A pump shaft that is bent or distorted should normally be __________. reconditioned by metalizing and machining straightened by applying heat and torsion replaced with a satisfactory spare repaired by a suitable welding process Pumps, Fans, and Blowers
A Why should the use of metallic or semi-metallic packing hooks or pullers be avoided on bronze or brass shafts, rods, plungers, or sleeves? Scoring may result. Bonnet corrosion may result. Heat transfer is restricted. Valve seat will be damaged. Pumps, Fans, and Blowers
D You suspect a problem with the centrifugal fire pump on your ship, and begin to slowly close the discharge valve. Your suspicion is confirmed when the __________. suction valve is closed off, and the discharge pressure begins to decrease suction valve is closed off, yet the relief valve does not lift discharge valve is 80% closed and the relief valve lifts discharge valve is closed off and there is no change in the discharge pressure Pumps, Fans, and Blowers
B A centrifugal pump may fail to deliver water when first started if the __________. seal ring is improperly located pump is not primed water seal pipe is plugged impeller is flooded Pumps, Fans, and Blowers
A Reduced capacity, accompanied by vibration and noise at the suction of a centrifugal pump, results from cavitation in the fluid being pumped. Cavitation describes the formation of __________. vapor pockets steam knock fluid friction water hammer action Pumps, Fans, and Blowers
A Pitting in the suction areas of a centrifugal pump bronze impeller is usually caused by __________. cavitation corrosion electrolysis abrasion Pumps, Fans, and Blowers
B Charring or glazing of the inner circumference of the packing rings in a centrifugal pump is caused by __________. under tightening the packing insufficient lubrication of the packing failure to seat the packing rings packing ring rotation Pumps, Fans, and Blowers
A Excessive air leakage into the suction side of a centrifugal pump would be indicated by which of the following operational problems? The pump delivers full capacity when started, but gradually slackens off to an abnormally low flow. The motor over current protective device continually shuts the pump down. The pump packing gland overheats after short operating periods. Pounding noises can be heard at the pump suction chest. Pumps, Fans, and Blowers
B Which of the following methods applies to how a vacuum is created by a jet pump or an eductor? A reciprocating plunger directly applying force to a fluid. A rapidly moving stream of fluid passing through a nozzle. A propeller drawing a fluid through a Venturi nozzle. Centrifugal force converted into potential energy. Pumps, Fans, and Blowers
D The three basic parts of any eductor are the nozzle, the suction chamber, and the __________. compressor injector siphon diffuser Pumps, Fans, and Blowers
C A distinguishing feature of an eductor, when compared to other pumps, is the __________. small size of impeller ease at which the wearing rings may be changed lack of moving parts discharge end being smaller than the suction end Pumps, Fans, and Blowers
A Which of the following statements represents the main difference between a stuffing box gland and a mechanical seal for sealing the shaft of a centrifugal pump? If packing fails, the pump can be kept running temporarily by tightening the gland, but if a mechanical seal fails it must be totally renewed to stop the leakage. Packed stuffing box glands are subject to wear, but mechanical seals are not. The sealing surface of a mechanical seal is parallel to the shaft, but the sealing surface of a packed gland is perpendicular to the shaft. Packed stuffing box glands must be cooled by the liquid being pumped, but mechanical seals do not require cooling. Pumps, Fans, and Blowers
C Which of the materials listed is used as the dynamic seal material on mechanical seals installed on most centrifugal pumps used in water service? Copper and carbon. Copper. Carbon. Bronze. Pumps, Fans, and Blowers
D Which of the following statements is true regarding mechanical seals? They may be used in lieu of conventional packing glands for any service other than saltwater. Once placed into service, leakage between the dynamic seal surfaces may be reduced by monthly adjustment of the spring compression. They are not suitable for use on fuel oil transfer pumps. They are normally lubricated and cooled by the fluid being pumped. Pumps, Fans, and Blowers
B Which of the listed types of seals is used effectively for pumps handling toxic or highly flammable liquids that cannot be permitted to escape into the atmosphere? Conventional stuffing box Double mechanical seal Rubber bellows mechanical seal External mechanical seal Pumps, Fans, and Blowers
B Mechanical shaft seals used on water service pumps require lubrication of the seal faces to minimize deposits of foreign matter on those surfaces. Which of the following pressures and lubricants are required? Water under negative pressure. Water under positive pressure. Oil under positive pressure. Oil under negative pressure. Pumps, Fans, and Blowers
C Which of the devices listed is used to maintain a snug interface between the rotating and stationary seal members shown in the illustration? Illustration GS-0071 notch and keyway bellows spring seal retaining ring Pumps, Fans, and Blowers
D Spring reinforced oil seals are generally installed with the tail or lip of the seal facing __________. Illustration GS-0152 away from the oil pressure being sealed away from the bearing housing recess toward the bearing preload washer toward the oil pressure being sealed Pumps, Fans, and Blowers
A One disadvantage of using a mechanical shaft seal instead of mechanical packing is that __________. seal failure usually requires the immediate removal of the pump from service it requires periodic disassembly and adjustment it is unsuitable for high pressure applications it is unsuitable for high temperature applications Pumps, Fans, and Blowers
D When installing a mechanical shaft seal on a pump, it is important to __________. run the pump "dry" for initial break-in of the shaft seal polish the seating faces with emery cloth prior to assembly make the final spring collar adjustments with the pump running ensure that correct spring pressure is applied to the seating faces Pumps, Fans, and Blowers
B One of the main differences between a propeller pump and a centrifugal pump is the absence of a __________. reciprocating piston in the centrifugal type pump volute in the propeller type pump velocity nozzle in the centrifugal type pump volute in the centrifugal type pump Pumps, Fans, and Blowers
D Which type of pump would normally be used to transfer fairly large quantities of fluids at relatively low pressures? gear type reciprocating type screw type propeller type Pumps, Fans, and Blowers
D Which of the pumping systems listed for use aboard ship will most likely use a propeller type pump? Fuel oil service booster system Fluid power transmission system Steering gear system Main circulating system Pumps, Fans, and Blowers
C Which of the following is NOT an identifiable characteristic of a steam reciprocating pump? Direct-acting Vertical Diffuser High-pressure Pumps, Fans, and Blowers
B Which of the following valve arrangements permits the reciprocating pump liquid piston to take suction from the suction chamber, and simultaneously discharge through the discharge chamber during the up and down strokes? Two relief valves, one on each of the liquid cylinder. Two sets of valves, one set each for suction and discharge located in the water chest. One set of valves in the water chest and another set in the liquid cylinder. Two sets of suction and discharge valves in the liquid cylinder. Pumps, Fans, and Blowers
C The suction-force principle of operation is a typical characteristic of __________. centrifugal pumps jet pumps reciprocating pumps propeller pumps Pumps, Fans, and Blowers
B Which of the listed devices is used to control the admission of steam to the steam cylinder of a reciprocating pump? Valve operating differential Pilot valve and operating rod Pump rod Crosshead arm Pumps, Fans, and Blowers
B Which of the listed reciprocating pump parts control the position of the pilot slide valve? Moving tappets Movement of the main piston through the steam cylinder Adjusting of the tappet collars Stay rods Pumps, Fans, and Blowers
D The total length of stroke in a reciprocating steam pump can be adjusted by __________. twisting the stay rod in a clockwise direction variations in the throttle adjustment increasing or decreasing the number of packing rings around the piston rod changing the setting of the tappet collars on the pilot valve operating rod Pumps, Fans, and Blowers
A When a reciprocating pump is operating at maximum speed, the cushioning valves should be __________. almost completely closed wide opened half opened 3/4 opened Pumps, Fans, and Blowers
B When securing a steam reciprocating pump, which of the valves listed should remain open? Water cylinder drain valve Steam cylinder drain valve Steam supply valve Steam exhaust valve Pumps, Fans, and Blowers
B When the danger of freezing exists, all steam driven reciprocating pumps and deck equipment should be __________. watched carefully while idled cycled at least once a day cycled once every week cycled once every 4 days Pumps, Fans, and Blowers
B Which of the lubricants listed is the best to use on a reciprocating pump rod? Vegetable oil. Graphite and oil. Engine oil. Oil mixed with kerosene. Pumps, Fans, and Blowers
C Which of the listed types of steam end piston rod packing should be used in a steam reciprocating pump? Reinforced rubber packing Wire impregnated high temperature packing High pressure graphite packing Low pressure braided asbestos packing Pumps, Fans, and Blowers
B The first step when resetting the slide valves on a duplex reciprocating pump is to __________. position the steam pistons on 3/4 stroke place the steam pistons in the mid stroke position ensure the balance piston is on the down stroke measure the present port openings to ensure reassembly will be the same Pumps, Fans, and Blowers
C When repacking a reciprocating pump with more than four rings of packing, the packing is cut square, installed with the ends abutted, and each succeeding ring staggered with the butted ends __________. 120 apart 180 apart 90 apart 45 apart Pumps, Fans, and Blowers
D To safely remove the piston rod packing from the steam end of a reciprocating pump, you should __________. open the throttle valve and 'blow' the old packing out do nothing, as this type of pump utilizes O-rings in lieu of packing open the steam chest and pry the packing loose with a scraper use a packing hook Pumps, Fans, and Blowers
A An inadequate reciprocating bilge pump discharge is most often caused by __________. clogged suction strainers clogged drain valves scarred cylinder walls defective intake valves Pumps, Fans, and Blowers
A Which of the following conditions would prevent a steam reciprocating pump from delivering its rated capacity? Excessive suction lift Air trapped in the discharge expansion chamber A leaking snifter valve allowing air to enter the suction side of the pump All of the above. Pumps, Fans, and Blowers
A When piston rod packing persists in leaking on a reciprocating steam pump, the cause may be __________. misalignment of the crosshead guide a loose tappet collar an open snifter valve clogged suction strainers Pumps, Fans, and Blowers
B A pounding noise occurring in one cylinder of a steam reciprocating general service pump could be caused by __________. lower than normal supply steam pressure improper adjustment of steam cushion valves loss of air charge in the pump discharge plenum chamber lower than normal supply steam temperature Pumps, Fans, and Blowers
A Excessive lost motion in the valve mechanism of a duplex reciprocating pump will cause the __________. pump to operate sluggishly pump to short stroke continuously at both ends of the stroke for both cylinders cushioning valves to wear pistons to stop in mid-stroke Pumps, Fans, and Blowers
C The output volume of a positive fixed displacement pump can be changed only by __________. changing the angle of the tilting plate moving the shaft trunnion block changing the speed of the pump moving the slide block and rotor Pumps, Fans, and Blowers
D What type of pump is shown in the illustration? Illustration GS-0144 Double screw rotary pump Deep well centrifugal pump Simplex reciprocating pump Triple screw rotary pump Pumps, Fans, and Blowers
D The function of the section labeled "C" in the device illustrated is to provide a/an __________. Illustration GS-0075 area for pump packing passage for sealing liquid to enter the pump bearing surface for the rotor shaft passage for gas to be discharged Pumps, Fans, and Blowers
D Which of the listed parts is used in a lobe-type rotary pump to allow for wear on the lobe edges? Spur gear adjusters Replaceable liner plates Casing gear thrust bearings Replaceable gib inserts Pumps, Fans, and Blowers
B Liquid is kept from leaking out at the shaft ends of a helical gear pump by __________. the use of shaft end caps a stuffing box overlapping spaces between gear teeth a roller bearing Pumps, Fans, and Blowers
C Positive displacement, helical gear pumps are well suited for pumping oil because __________. these pumps are designed with extreme tooth angles it is not necessary to closely maintain design clearances with this pump they are essentially self-priming and capable of a high suction lift stuffing boxes eliminate the leakage problems usually associated with other gear pumps Pumps, Fans, and Blowers
D The capacity of a gear type rotary pump, when operated at a constant speed, will decrease with an increase in the pump __________. suction pressure discharge volume torque rating rotor clearances Pumps, Fans, and Blowers
A A spur gear pump should be operated with the discharge valves __________. fully opened halfway opened throttled slightly opened Pumps, Fans, and Blowers
C How does the viscosity of a fluid being pumped affect the operation of a spur gear pump? The pump can only be used for fluids of high viscosity. The pump can only be used for light oils. The viscosity of the fluid is relatively unimportant in the pump operation. The pump cannot handle fluids more viscous than lubricating oil. Pumps, Fans, and Blowers
A Why is the discharge pressure of a herringbone gear pump steadier than the discharge pressure of a simple spur gear pump? One discharge phase begins before the previous discharge phase has been completed. The herringbone gear pump has four spur gears instead of two. Clearance between the gear teeth and casing is smaller. The gear teeth are smaller than those of the simple spur gear pump. Pumps, Fans, and Blowers
B One of the main differences between the various types of screw pumps is in the __________. stuffing box diameter pitch of the screws direction of rotation of the screws type of driving gears Pumps, Fans, and Blowers
A An increase in rotor clearances in a rotary pump will __________. decrease pump capacity decrease pump cavitation increase discharge pressure decrease reaction ring clearance Pumps, Fans, and Blowers
C The pressure of a liquid leaving the pump can be referred to as the __________. suction head net positive suction head discharge head total head Pumps, Fans, and Blowers
A If the existing vapor pressure is subtracted from the indicated pressure at the pump suction, the remainder is the __________. apparent net positive suction head pump head discharge head total suction head Pumps, Fans, and Blowers
B Which of the following terms is used to identify the pressure of a liquid entering a centrifugal pump? Discharge head Suction head Pump head Total head Pumps, Fans, and Blowers
A A pump is defined as a device that __________. imparts energy to a fluid to move it from point "A" to point "B" creates a vacuum to move a liquid in all installations produces pressure is to develop a pressure differential Pumps, Fans, and Blowers
C If the existing vapor pressure is subtracted from the indicated pressure at the pump suction, the remainder is the __________. total suction head pump head apparent net positive suction head discharge head Pumps, Fans, and Blowers
D Which of the following terms is used to identify the pressure of a liquid entering a centrifugal pump? Total head Discharge head Pump head Suction head Pumps, Fans, and Blowers
D Item "B" in the pump illustration is the __________. Illustration GS-0129 wearing ring stuffing box shaft sleeve packing gland Pumps, Fans, and Blowers
B Which of the materials listed is used as the dynamic seal material on mechanical seals installed on most centrifugal pumps used in water service? Bronze. Carbon. Copper and carbon. Copper. Pumps, Fans, and Blowers
D Which of the following statements is true regarding mechanical seals? They may be used in lieu of conventional packing glands for any service other than saltwater. Once placed into service, leakage between the dynamic seal surfaces may be reduced by monthly adjustment of the spring compression. They are not suitable for use on fuel oil transfer pumps. They are normally lubricated and cooled by the fluid being pumped. Pumps, Fans, and Blowers
C Air leakage between the shaft and stuffing box packing in a centrifugal pump is prevented by __________. lantern rings between the packing rings a compressed packing gland a liquid seal the stuffing box gland Pumps, Fans, and Blowers
C The shaft sleeve for the pump illustrated is identified by the item numbered as
__________. Illustration GS-0143
68 27 14 17 Pumps, Fans, and Blowers
C Water leaking from a pump packing gland is kept away from the bearing housing by the use of __________. shaft sleeves water seals water flingers lantern rings Pumps, Fans, and Blowers
B Why are removable sleeves installed on centrifugal pump shafts? They can be removed when it is necessary to lighten the weight of the pump. They can be economically replaced as they wear out. They increase the strength of the shaft. They make it easier to replace the pump shaft packing. Pumps, Fans, and Blowers
C The function of seal cages, or lantern rings installed in the centrifugal pump stuffing boxes, is to __________. cool the shaft lubricate the packing distribute the sealing liquid within the stuffing box seal air from entering along the shaft Pumps, Fans, and Blowers
C Permanent centrifugal pump shaft damage due to erosion, corrosion, and wear at the stuffing box is usually prevented by __________. a hardened sprayed metal coating internally flooded lantern rings renewable sleeves wearing rings Pumps, Fans, and Blowers
C A recirculating, or bleed off line is installed on a centrifugal pump in order to __________. equalize pressure on both sides of the suction valve disc establish a back pressure at the labyrinth seal to eliminate leakage prevent the pump from overheating when operating at shutoff head decrease the net positive suction head Pumps, Fans, and Blowers
C Which of the following statements represents the main difference between a stuffing box gland and a mechanical seal for sealing the shaft of a centrifugal pump? Packed stuffing box glands are subject to wear, but mechanical seals are not.
 
Packed stuffing box glands must be cooled by the liquid being pumped, but mechanical seals do not require cooling. If packing fails, the pump can be kept running temporarily by tightening the gland, but if a mechanical seal fails it must be totally renewed to stop the leakage. The sealing surface of a mechanical seal is parallel to the shaft, but the sealing surface of a packed gland is perpendicular to the shaft. Pumps, Fans, and Blowers
B The simplest method to use for determining if a centrifugal pump is operating as designed, is to __________. use a clamp on ammeter and compare the readings to past records close off the discharge valve, and watch for a rise in pressure closely observe the pump discharge temperature momentarily close off the suction valve, and watch for a rise in pressure Pumps, Fans, and Blowers
B A centrifugal bilge pump requires priming __________. primarily to lubricate the shaft seals due to the inability of this type of pump to lift water to cover the suction (eye) of the impeller in order to overcome the potential energy of water in the discharge line to initially unload the pump by having its head pressure equal to discharge pressure Pumps, Fans, and Blowers
B A centrifugal bilge pump requires priming __________. primarily to lubricate the shaft seals due to the inability of this type of pump to lift water to cover the suction (eye) of the impeller in order to overcome the potential energy of water in the discharge line to initially unload the pump by having its head pressure equal to discharge pressure Pumps, Fans, and Blowers
B If a centrifugal pump were continually operated with the discharge valve closed, the __________. motor controller overload would open pump would eventually overheat relief valve would continuously cycle open motor would overheat Pumps, Fans, and Blowers
C Excessive air leakage into the suction side of a centrifugal pump would be indicated by which of the following operational problems? The motor over current protective device continually shuts the pump down.
 
o
The pump packing gland overheats after short operating periods. The pump delivers full capacity when started, but gradually slackens off to an abnormally low flow. Pounding noises can be heard at the pump suction chest. Pumps, Fans, and Blowers
A Pitting in the suction areas of a centrifugal pump bronze impeller is usually caused by __________. cavitation abrasion corrosion electrolysis Pumps, Fans, and Blowers
B Reduced capacity, accompanied by vibration and noise at the suction of a centrifugal pump, results from cavitation in the fluid being pumped. Cavitation describes the formation of __________. steam knock vapor pockets fluid friction water hammer action Pumps, Fans, and Blowers
D You suspect a problem with the centrifugal fire pump on your ship, and begin to slowly close the discharge valve. Your suspicion is confirmed when the __________. suction valve is closed off, and the discharge pressure begins to decrease discharge valve is 80% closed and the relief valve lifts suction valve is closed off, yet the relief valve does not lift discharge valve is closed off and there is no change in the discharge pressure Pumps, Fans, and Blowers
D A centrifugal pump may fail to deliver water when first started if the __________. seal ring is improperly located water seal pipe is plugged impeller is flooded pump is not primed Pumps, Fans, and Blowers
D Charring or glazing of the inner circumference of the packing rings in a centrifugal pump is caused by __________. failure to seat the packing rings packing ring rotation under tightening the packing insufficient lubrication of the packing Pumps, Fans, and Blowers
B When repacking a stuffing box fitted with a lantern ring, which of the following precautions should be observed? For good lubrication, apply a fine grade lapping compound between the shaft and packing. Replace all of the packing rings. Block off the sealing water connection. Be certain that all packing is fitted loosely to the shaft. Pumps, Fans, and Blowers
C A centrifugal pump gradually develops insufficient discharge pressure. What corrective action is required? Throttle in on the suction valve. Replace the lantern rings. Replace the wearing rings. Throttle in on the discharge valve. Pumps, Fans, and Blowers
A When renewing spiral packing in a centrifugal pump stuffing box, after the packing is firmly seated, the packing gland nuts should be __________. loosened, and then retightened with the pump running under normal conditions loosened until the gland clears the stuffing box left in that position tightened an additional 10% to compress the packing Pumps, Fans, and Blowers
D What should be done if localized scoring is discovered on a pump shaft sleeve during routine maintenance inspection? Reassemble the pump and set the governor to obtain a slower speed. Reassemble the pump and provide more water leak off for lubrication. Check for parallel alignment of the sleeve radial face to the sleeve bore. Correct the cause of scoring and install a new shaft sleeve. Pumps, Fans, and Blowers
A Why should the use of metallic or semi-metallic packing hooks or pullers be avoided on bronze or brass shafts, rods, plungers, or sleeves? Scoring may result. Valve seat will be damaged. Heat transfer is restricted. Bonnet corrosion may result. Pumps, Fans, and Blowers
A A pump shaft that is bent or distorted should normally be __________. replaced with a satisfactory spare straightened by applying heat and torsion repaired by a suitable welding process reconditioned by metalizing and machining Pumps, Fans, and Blowers
A When installing a mechanical shaft seal on a pump, it is important to __________. ensure that correct spring pressure is applied to the seating faces polish the seating faces with emery cloth prior to assembly run the pump "dry" for initial break-in of the shaft seal make the final spring collar adjustments with the pump running Pumps, Fans, and Blowers
A Which of the following statements is true concerning centrifugal pumps? A flow is developed by imparting kinetic energy to the fluid by the rotation of an impeller. They operate best under negative suction pressure conditions. They are particularly well suited for pumping high viscosity fluids. They operate more efficiently when mounted in a horizontal position. Pumps, Fans, and Blowers
D The primary function of a centrifugal pump volute is to __________. develop a high velocity liquid limit hydraulic end thrust initiate flow convert velocity to pressure Pumps, Fans, and Blowers
C The basic function of the centrifugal pump impeller is to __________. separate air from the liquid being pumped convert the potential energy of the liquid to kinetic energy directly increase the velocity of the liquid being pumped directly increase the pressure of the liquid being pumped Pumps, Fans, and Blowers
C Which of the following statements is true concerning centrifugal pumps? They are always mounted in a horizontal position. They are started with the discharge valve opened. The flow of liquid is developed by imparting energy due to the rotation of an impeller. They are particularly suited for pumping high viscosity fluids. Pumps, Fans, and Blowers
D The function of the section labeled "C" in the device illustrated is to provide a/an __________. Illustration GS-0075 passage for sealing liquid to enter the pump bearing surface for the rotor shaft area for pump packing passage for gas to be discharged Pumps, Fans, and Blowers
A Which of the devices listed is used to maintain a snug interface between the rotating and stationary seal members shown in the illustration? Illustration GS-0071 spring notch and keyway seal retaining ring bellows Pumps, Fans, and Blowers
A Which of the listed parts is used in a lobe-type rotary pump to allow for wear on the lobe edges? Replaceable gib inserts Casing gear thrust bearings Spur gear adjusters Replaceable liner plates Pumps, Fans, and Blowers
C What type of pump is shown in the illustration? Illustration GS-0144 Deep well centrifugal pump Simplex reciprocating pump Triple screw rotary pump Double screw rotary pump Pumps, Fans, and Blowers
D The output volume of a positive fixed displacement pump can be changed only by __________. moving the slide block and rotor changing the angle of the tilting plate moving the shaft trunnion block changing the speed of the pump Pumps, Fans, and Blowers
B One of the main differences between the various types of screw pumps is in the __________. stuffing box diameter pitch of the screws direction of rotation of the screws type of driving gears Pumps, Fans, and Blowers
D Spring reinforced oil seals are generally installed with the tail or lip of the seal facing __________. Illustration GS-0152 away from the bearing housing recess toward the bearing preload washer away from the oil pressure being sealed toward the oil pressure being sealed Pumps, Fans, and Blowers
B Which of the listed types of seals is used effectively for pumps handling toxic or highly flammable liquids that cannot be permitted to escape into the atmosphere? Rubber bellows mechanical seal Double mechanical seal External mechanical seal Conventional stuffing box Pumps, Fans, and Blowers
A One disadvantage of using a mechanical shaft seal instead of mechanical packing is that __________. seal failure usually requires the immediate removal of the pump from service it is unsuitable for high pressure applications it requires periodic disassembly and adjustment it is unsuitable for high temperature applications Pumps, Fans, and Blowers
D A spur gear pump should be operated with the discharge valves __________. slightly opened halfway opened throttled fully opened Pumps, Fans, and Blowers
A An increase in rotor clearances in a rotary pump will __________. decrease pump capacity decrease pump cavitation increase discharge pressure decrease reaction ring clearance Pumps, Fans, and Blowers
D Positive displacement, helical gear pumps are well suited for pumping oil because __________. it is not necessary to closely maintain design clearances with this pump these pumps are designed with extreme tooth angles stuffing boxes eliminate the leakage problems usually associated with other gear pumps they are essentially self-priming and capable of a high suction lift Pumps, Fans, and Blowers
D The capacity of a gear type rotary pump, when operated at a constant speed, will decrease with an increase in the pump __________. discharge volume suction pressure torque rating rotor clearances Pumps, Fans, and Blowers
B How does the viscosity of a fluid being pumped affect the operation of a spur gear pump? The pump can only be used for light oils. The viscosity of the fluid is relatively unimportant in the pump operation. The pump cannot handle fluids more viscous than lubricating oil. The pump can only be used for fluids of high viscosity. Pumps, Fans, and Blowers
A Why is the discharge pressure of a herringbone gear pump steadier than the discharge pressure of a simple spur gear pump? One discharge phase begins before the previous discharge phase has been completed. The gear teeth are smaller than those of the simple spur gear pump. The herringbone gear pump has four spur gears instead of two. Clearance between the gear teeth and casing is smaller. Pumps, Fans, and Blowers
D Which of the following is NOT an identifiable characteristic of a steam reciprocating pump? Vertical Direct-acting High-pressure Diffuser Pumps, Fans, and Blowers
D Which of the following valve arrangements permits the reciprocating pump liquid piston to take suction from the suction chamber, and simultaneously discharge through the discharge chamber during the up and down strokes? Two sets of suction and discharge valves in the liquid cylinder. One set of valves in the water chest and another set in the liquid cylinder. Two relief valves, one on each of the liquid cylinder. Two sets of valves, one set each for suction and discharge located in the water chest. Pumps, Fans, and Blowers
D Which of the listed devices is used to control the admission of steam to the steam cylinder of a reciprocating pump? Pump rod Valve operating differential Crosshead arm Pilot valve and operating rod Pumps, Fans, and Blowers
B Which of the listed reciprocating pump parts control the position of the pilot slide valve? Adjusting of the tappet collars Movement of the main piston through the steam cylinder Moving tappets Stay rods Pumps, Fans, and Blowers
A The total length of stroke in a reciprocating steam pump can be adjusted by __________. changing the setting of the tappet collars on the pilot valve operating rod variations in the throttle adjustment twisting the stay rod in a clockwise direction increasing or decreasing the number of packing rings around the piston rod Pumps, Fans, and Blowers
B When securing a steam reciprocating pump, which of the valves listed should remain open? Water cylinder drain valve Steam cylinder drain valve Steam exhaust valve Steam supply valve Pumps, Fans, and Blowers
B When the danger of freezing exists, all steam driven reciprocating pumps and deck equipment should be __________. watched carefully while idled cycled at least once a day cycled once every 4 days cycled once every week Pumps, Fans, and Blowers
B Excessive lost motion in the valve mechanism of a duplex reciprocating pump will cause the __________. cushioning valves to wear pump to operate sluggishly pump to short stroke continuously at both ends of the stroke for both cylinders pistons to stop in mid-stroke Pumps, Fans, and Blowers
B An inadequate reciprocating bilge pump discharge is most often caused by __________. scarred cylinder walls clogged suction strainers clogged drain valves defective intake valves Pumps, Fans, and Blowers
C A pounding noise occurring in one cylinder of a steam reciprocating general service pump could be caused by __________. lower than normal supply steam temperature loss of air charge in the pump discharge plenum chamber improper adjustment of steam cushion valves lower than normal supply steam pressure Pumps, Fans, and Blowers
D When piston rod packing persists in leaking on a reciprocating steam pump, the cause may be __________. a loose tappet collar an open snifter valve clogged suction strainers misalignment of the crosshead guide Pumps, Fans, and Blowers
C Which of the following conditions would prevent a steam reciprocating pump from delivering its rated capacity? Air trapped in the discharge expansion chamber A leaking snifter valve allowing air to enter the suction side of the pump Excessive suction lift All of the above. Pumps, Fans, and Blowers
B When repacking a reciprocating pump with more than four rings of packing, the packing is cut square, installed with the ends abutted, and each succeeding ring staggered with the butted ends __________. 45 apart 90 apart 120 apart 180 apart Pumps, Fans, and Blowers
A To safely remove the piston rod packing from the steam end of a reciprocating pump, you should __________. use a packing hook do nothing, as this type of pump utilizes O-rings in lieu of packing open the throttle valve and 'blow' the old packing out open the steam chest and pry the packing loose with a scraper Pumps, Fans, and Blowers
A Which of the listed types of steam end piston rod packing should be used in a steam reciprocating pump? High pressure graphite packing Wire impregnated high temperature packing Low pressure braided asbestos packing Reinforced rubber packing Pumps, Fans, and Blowers
B Which of the lubricants listed is the best to use on a reciprocating pump rod? Oil mixed with kerosene. Graphite and oil. Engine oil. Vegetable oil. Pumps, Fans, and Blowers
D The first step when resetting the slide valves on a duplex reciprocating pump is to __________. position the steam pistons on 3/4 stroke measure the present port openings to ensure reassembly will be the same ensure the balance piston is on the down stroke place the steam pistons in the mid stroke position Pumps, Fans, and Blowers
B If you have a duplex, single acting, reciprocating pump making 140 strokes/minute with a 3" diameter cylinder, and a 12" stroke with a 94% volumetric efficiency, what is the capacity of this pump? 58 gpm 48 gpm 38 gpm 28 gpm Pumps, Fans, and Blowers
C If you have a duplex, single acting, reciprocating pump making 140 strokes/minute with a 3" diameter cylinder, and a 12" stroke with a 94% volumetric efficiency, what is the capacity of this pump? 28 gpm 38 gpm 48 gpm 58 gpm Pumps, Fans, and Blowers
A The suction-force principle of operation is a typical characteristic of __________. reciprocating pumps jet pumps centrifugal pumps propeller pumps Pumps, Fans, and Blowers
B Which of the pumping systems listed for use aboard ship will most likely use a propeller type pump? Steering gear system Main circulating system Fuel oil service booster system Fluid power transmission system Pumps, Fans, and Blowers
C One of the main differences between a propeller pump and a centrifugal pump is the absence of a __________. velocity nozzle in the centrifugal type pump volute in the centrifugal type pump volute in the propeller type pump reciprocating piston in the centrifugal type pump Pumps, Fans, and Blowers
D Which type of pump would normally be used to transfer fairly large quantities of fluids at relatively low pressures? reciprocating type screw type gear type propeller type Pumps, Fans, and Blowers
B The three basic parts of any eductor are the nozzle, the suction chamber, and the __________. injector diffuser compressor siphon Pumps, Fans, and Blowers
D A distinguishing feature of an eductor, when compared to other pumps, is the __________. discharge end being smaller than the suction end ease at which the wearing rings may be changed small size of impeller lack of moving parts Pumps, Fans, and Blowers
C Which of the following methods applies to how a vacuum is created by a jet pump or an eductor? A propeller drawing a fluid through a Venturi nozzle. A reciprocating plunger directly applying force to a fluid. A rapidly moving stream of fluid passing through a nozzle. Centrifugal force converted into potential energy. Pumps, Fans, and Blowers
C The simplest method to use for determining if a centrifugal pump is operating as designed, is to __________. use a clamp on ammeter and compare the readings to past records closely observe the pump discharge temperature close off the discharge valve, and watch for a rise in pressure momentarily close off the suction valve, and watch for a rise in pressure Pumps, Fans, and Blowers
A Both existing centrifugal cooling water pumps will be replaced by two of a higher GPM. Only one pump is used in normal operation and there will be no modifications to their discharge piping. This is an operational concern since increased velocity will increase pipe erosion. What is the fluid velocity in feet/minute in the discharge piping with new pumps, given the following data?
{{{
Existing Pump:
Capacity = 200 GPM
Internal discharge pipe Diameter = 7 1/2 inches
Present discharge piping velocity = 87.088 feet/minute

New Pump: 
Capacity = 230 GPM
New velocity 'V' = ?}}}
100.149 ft./min. 112.151 ft./min. 78.719 ft./min. 126.151 ft./min. Pumps, Fans, and Blowers
A On disassembling a centrifugal pump for overhaul, the third engineer reports holes drilled axially in the back side of a single suction closed impeller. The reason for the these holes is which of the following? To reduce the axial thrust forces on the impeller To allow for water to recirculate for impeller cooling To reduce the power required for the pump To fit a puller for removing the impeller Pumps, Fans, and Blowers
B The assistant engineer reports an installed centrifugal pump has a history of running higher than normal amperage since new construction. Capacity and discharge head for the pump are more than adequate. All other system parameters are normal. The best way to reduce the pump load is to do which of the following? By replace the pump with a new pump. By reducing the impeller diameter. By install a bypass line between the pump discharge and suction. By place another equal size pump in parallel. Pumps, Fans, and Blowers
B Which of the following statements is true concerning centrifugal pumps? They operate more efficiently when mounted in a horizontal position. A flow is developed by imparting kinetic energy to the fluid by the rotation of an impeller. They operate best under negative suction pressure conditions. They are particularly well suited for pumping high viscosity fluids. Pumps, Fans, and Blowers
D Pitting in the suction areas of a centrifugal pump bronze impeller is usually caused by __________. corrosion abrasion electrolysis cavitation Pumps, Fans, and Blowers
C When ordering a new centrifugal pump for installation, what is the advantage of a pump with a double suction impeller over a single suction impeller? Pump capacity will be doubled. The pump can be used with a reversible drive. The pump will experience less axial thrust. The pump will experience less water turbulence. Pumps, Fans, and Blowers
B A pumping system utilizing a centrifugal pump is designed for a specific discharge head in feet. What happens to the pump's discharge pressure when the Specific Gravity (SG) of the fluid pumped changes? SG will change the system's head. Lower SG fluids will cause the discharge pressure to decline. Higher SG fluids will cause the discharge pressure to decline. Pump discharge pressure will remain the same. Pumps, Fans, and Blowers
A After a disassembly of a single stage centrifugal pump, one finds the outer circumference of the impeller badly pitted and worn. Not having a spare impeller on board, it is decided to turn down the impeller to eliminate the wear/pitting. What will be the pump capacity, in GPM, after the reduction of impeller diameter by 0.5 inches? GIVEN: Original pump capacity = 30 GPM Original impeller diameter = 8 in. 28.12 GPM 24.78 GPM Capacity would not change. 26.37 GPM Pumps, Fans, and Blowers
A One is informed by the owner that two of the vessel's electrically driven centrifugal cooling water pumps will be replaced with two of higher capacity pumps. No modification of existing piping will be involved. What should be your concerns from an operational perspective? Upgrading of circuit breakers and controllers and possible increased erosion of discharge piping due to increased system velocities. Piping should be of no concern since it is designed with a safety factor. Electrical power should be of concern. Electrical power should be of no concern due to safety margins designed into power systems. Increased erosion may be a long term consideration. One should not be concerned operationally since all systems are designed with future modifications/upgrades in mind. Pumps, Fans, and Blowers
D When repacking a stuffing box fitted with a lantern ring, which of the following precautions should be observed? For good lubrication, apply a fine grade lapping compound between the shaft and packing. Block off the sealing water connection. Be certain that all packing is fitted loosely to the shaft. Replace all of the packing rings. Pumps, Fans, and Blowers
A When renewing spiral packing in a centrifugal pump stuffing box, after the packing is firmly seated, the packing gland nuts should be __________. loosened, and then retightened with the pump running under normal conditions left in that position tightened an additional 10% to compress the packing loosened until the gland clears the stuffing box Pumps, Fans, and Blowers
C Why should the use of metallic or semi-metallic packing hooks or pullers be avoided on bronze or brass shafts, rods, plungers, or sleeves? Bonnet corrosion may result. Valve seat will be damaged. Scoring may result. Heat transfer is restricted. Pumps, Fans, and Blowers
B A pump shaft that is bent or distorted should normally be __________. reconditioned by metalizing and machining replaced with a satisfactory spare repaired by a suitable welding process straightened by applying heat and torsion Pumps, Fans, and Blowers
B When installing a mechanical shaft seal on a pump, it is important to __________. make the final spring collar adjustments with the pump running ensure that correct spring pressure is applied to the seating faces run the pump "dry" for initial break-in of the shaft seal polish the seating faces with emery cloth prior to assembly Pumps, Fans, and Blowers
C Your centrifugal ballast pump is producing a pressure less than the designed discharge pressure. What could be the cause? Excessive high suction head. Excessive pump speed. Worn wearing rings. Pump misalignment. Pumps, Fans, and Blowers
A The shipyard has just reassembled an overhauled centrifugal pump. On testing, water is coming from the mechanical seal area. Which of the following are likely reasons for the leakage? The shaft o-ring was not installed. The pump was started with the discharge valve closed. The pump was started with the suction valve closed. The pump was air bound. Pumps, Fans, and Blowers
A While pumping ballast the Chief Mate reports there is a decrease in vacuum on the pump suction when drawing from a partially full saddle tank. Which of the following could be a possible cause? An air leak in the suction piping from the tank. The suction valve from the pump is partially closed. The tank suction valve is partially closed. The pump suction strainer is clogged. Pumps, Fans, and Blowers
A While making a round in the lower engine room you discover a leak in the suction pipe to the main salt water pump. How would proceed to correct this problem? Use a type of banded patch (from a simple gasket with hose clamps to forge clamp style) on the pipe to seal the hole in the pipe until a permanent repair can be made. Wrap the leaky section of pipe with duct tape to slow the leak down. Let the pipe leak until a permanent repair can be made at your next port call. Monitor the leak to see if it worsens. Pumps, Fans, and Blowers
C When reviewing log books, the main salt water cooling pump discharge pressure has decreased in the three years since overhaul. Which of the following would most likely be the cause of the problem. Bus frequency lower than normal. Worn pump shaft bearings. Increased impeller and wear ring clearance. Fouled suction strainer. Pumps, Fans, and Blowers
A When opening a ballast pump for inspection, the wear ring clearance is found to be approaching maximum. Which of the following would be expected? Pump capacity would be decreased. Pump vibration would be decreased. Pump discharge pressure would be increased. Pump lift would be increased. Pumps, Fans, and Blowers
B Referring to illustrated diagram, what type of HVAC system is shown? Illustration GS-RA-42 A dual duct system A terminal reheat system A variable air volume system A single zone system Pumps, Fans, and Blowers
D A spur gear pump should be operated with the discharge valves __________. halfway opened throttled slightly opened fully opened Pumps, Fans, and Blowers
A Traditionally, which of the listed refrigerants has been more suitable than the others for use in a centrifugal refrigeration compressor? R-11 Carbon dioxide Ammonia R-12 Refrigeration & Air Conditioning
D Which of the fluids listed is suitable for use as a secondary refrigerant? Carbon dioxide Cuprous chloride Methyl alcohol Brine Refrigeration & Air Conditioning
A R-134a is often the replacement for which older type of refrigerant? R-12 R-123 R-11 R-22 Refrigeration & Air Conditioning
B Which of the following substances is normally classified as a low pressure refrigerant? R-22 R-123 R-134A R-12 Refrigeration & Air Conditioning
B Which of the following refrigerants is chlorine free and safe regarding atmospheric ozone depletion? R-11 R-134a R-12 R-22 Refrigeration & Air Conditioning
A What is the most important consideration in selecting a lubricating oil for use in a refrigeration compressor? have a low pour point have a high wax content have a high freezing point have a low viscosity index Refrigeration & Air Conditioning
A Properties of a good refrigeration compressor lubricating oil include which of the following? low wax content high pour point high viscosity All of the above. Refrigeration & Air Conditioning
A The lubrication oil in the crankcase of a refrigeration compressor that is shut down is heated. For what purpose is this done? reduce absorption of refrigerant by the oil prevent refrigerant vaporization remove wax and gum remove entrained water Refrigeration & Air Conditioning
B If you mistakenly change from a lower pour point lubricant to a higher pour point lubricant in a refrigeration system, what will be the result? compressor lubrication will be improved oil may congeal in the evaporator compressor valves will be damaged oil will not leave the crankcase Refrigeration & Air Conditioning
C What is the color coding for a storage container of R-134a refrigerant? green grey light blue purple Refrigeration & Air Conditioning
D The term 'oil foaming' in refrigeration practice, is used to describe what event? release of dissolved lubricant from the refrigerant in the crankcase sudden evaporation of entrapped moisture from the crankcase lubricant sudden evaporation of entrapped air from the refrigerant liquid release of miscible refrigerant from the lubricant in the crankcase Refrigeration & Air Conditioning
D The gas that exists in the stratosphere forming a protective shield that helps to protect the environment from the harmful effects ultraviolet radiation is called what? nitrogen oxygen radon ozone Refrigeration & Air Conditioning
B The "tare weight" of a refrigerant storage cylinder refers to what weight? the total weight of a fully charged cylinder the weight of an empty cylinder the weight of a cylinder AND its current contents the maximum weight of the refrigerant allowed Refrigeration & Air Conditioning
B At ambient temperature and atmospheric pressure, what is the status of R-134a? sub cooled gas odorless gas corrosive liquid superheated liquid Refrigeration & Air Conditioning
D Regarding heat transfer principles, which of the following is true? Heat transfer always flows from cold regions to hot regions. A gas can transfer heat more efficiently than a liquid. Steel pipe can transfer heat more efficiently than copper pipe. Heat transfer always flows from hot regions to cold regions. Refrigeration & Air Conditioning
A Refrigerant entering the compressor of a refrigeration system should be in which of the following conditions? Low pressure vapor High pressure liquid High pressure vapor Low pressure liquid Refrigeration & Air Conditioning
C What is the physical state and pressure condition of refrigerant as it enters the condenser of a typical refrigeration system. low pressure vapor low pressure liquid high pressure vapor high pressure liquid Refrigeration & Air Conditioning
D What is the physical state and pressure condition of refrigerant as it leaves a receiver in a typical refrigeration system? low pressure vapor high pressure vapor low pressure liquid high pressure liquid Refrigeration & Air Conditioning
D What is the pressure and condition of the refrigerant entering the receiver of a refrigeration system? superheated low pressure vapor sub cooled low pressure liquid superheated high pressure vapor sub cooled high pressure liquid Refrigeration & Air Conditioning
C When repairing a refrigeration system, a swaging tool set would be used to carry out which of the following operations? Swaging tools are no longer used with repairing refrigeration systems due to progressive changes in the tool industry. Swaging tools are used to remove any sweated edges formed on the tubing while soldering. Swaging tools can be used to expand an end of one tube to fit onto a tube of the same original outside diameter. Swaging tools are used during the breaking-in of refrigeration compressors and drive motors. Refrigeration & Air Conditioning
A In a refrigeration system, once the gage manifold hoses are attached to the compressor service valve connections and properly purged, what should be the status of the manifold valves and the service valves when the purpose for attachment is to read system pressures? both manifold hand valves should be closed and the compressor Service Valves should be cracked-off their back seats both manifold hand valves should be open and the compressor Service Valves should be cracked-off their back seats both manifold hand valves should be open and the compressor Service Valves should both be back-seated both manifold hand valves should be open and the compressor Service Valves should both be front-seated Refrigeration & Air Conditioning
B Which pair of the illustrated service gauge manifold sets would require switching hoses when transitioning from a dehydration evacuation to refrigerant charging? Illustration GS-RA-30 A and B B and D C and D D and A Refrigeration & Air Conditioning
B With a service gauge manifold set connected to a refrigerant compressor as shown in the illustration, which arrangement of the gauge manifold set valves and compressor Service Valves would allow for simultaneous reading of the compressor suction and discharge pressures? Illustration GS-RA-03 Valves "2" and "5" both open, along with valves "1" and "6" both open in the mid-position. Valves "2" and "5" both closed, along with valves "1" and "6" both cracked open off their backseats. Valves "2" and "5" both open, along with valves "1" and "6" both front-seated. Valves "2" and "5" both closed, along with valves "1" and "6" both back-seated. Refrigeration & Air Conditioning
B When purging a refrigeration gage manifold using system pressure as the source of refrigerant for purging, which of the fittings listed is normally tightened LAST? the high pressure hose fitting at the gage manifold high pressure connection the low pressure hose fitting at the suction service valve service port the low pressure hose fitting at the gage manifold low pressure connection the high pressure hose fitting at the discharge service valve service port Refrigeration & Air Conditioning
C Which of the following statements is true concerning the illustrated gauge manifold set? Illustration GS-RA-01 Closing the valve labeled "G" isolates the hose labeled "H" from the gauge labeled "A". The valves labeled "G" and "C" must both be open to read system pressures on the respective gages labeled "A" and "B". Closing the valve labeled "G" isolates the hose labeled "H" from the hose labeled "J". Opening fully and back seating the valve labeled "G" isolates the gauge labeled "A" from the hose labeled "H". Refrigeration & Air Conditioning
A In a refrigeration system, from what location would air and non-condensable gases be removed? the top of the condenser purge connection expansion valve equalizer connection compressor oil fill connection the bottom of the receiver drain connection Refrigeration & Air Conditioning
D Loss of refrigerant during the process of purging of air and non-condensable gases can be kept to a minimum by what action? purging through the discharge service valve rather than the top of the condenser purging through the top of the receiver rather than the top of the condenser purging through a dehydrator cracking the purge valve briefly and allowing the refrigerant to re-settle between purges Refrigeration & Air Conditioning
C Before charging a refrigeration unit, unless quick disconnect fittings are used, the refrigerant charging hoses should be prepared in what way? they should be flushed with clean refrigerant oil they should be cleaned with carbon tetrachloride they should be purged with refrigerant they should be warmed in an oven Refrigeration & Air Conditioning
C Concerning the charging of refrigerant into a vapor compression refrigerating system, which of the following is true? when charging as a liquid it should be to the low side only when charging as a liquid it may be to the low or high side when charging as a liquid it should be to the high side only when charging as a vapor it should be directly to the receiver only Refrigeration & Air Conditioning
D The amount of HCFC-123 in a storage cylinder is measured by what means? volume saturation pressure saturation temperature weight Refrigeration & Air Conditioning
C Which of the illustrated valves is used to gain access to a hermetic system and features a Schrader core valve which is unseated by the core depressor of hose fitting when attached? Illustration GS-RA-69 B A D C Refrigeration & Air Conditioning
A How should small appliances with less than three pounds of refrigerant be charged with refrigerant? vapor charged either vapor or liquid charged liquid charged initially liquid charged and then topped with a vapor charge Refrigeration & Air Conditioning
C If passive recovery is used on a small appliance fitted with a capillary tube as a metering device with a non-operating compressor, the recovery should be made through what means? recovery from the low side only by venting to atmosphere, cannot be recovered recovery from both the high and low sides recovery from the high side only Refrigeration & Air Conditioning
B In a low pressure refrigeration system, excessive running of the purge recovery unit generally indicates which probable condition? faulty purge system vent valve system leaks on the low side system leaks on the high side overcharged system Refrigeration & Air Conditioning
A In a low-pressure centrifugal chiller, what is meant by the term 'high efficiency purge unit? Those purge units which discharge very little refrigerant with the air being removed. Those purge units which draw very little electrical power. Those purge units which need the least amount of on-going Maintenance. Those purge units which discharge the highest percentage of refrigerant with the air being removed. Refrigeration & Air Conditioning
B During normal operation, traditionally, how has most of the refrigerant released to the atmosphere from low pressure systems? through a leaking rupture disk through the purge unit vent through the compressor shaft seal through water-side system leaks Refrigeration & Air Conditioning
C Charging liquid HCFC-123 into a system under a deep vacuum could cause what to happen unless necessary precautions are taken? air and moisture to enter the receiver the purge unit to operate system secondary refrigerant to freeze rupture disk to rupture Refrigeration & Air Conditioning
A After the refrigerant has been recovered, leaks repaired if necessary, the system ideally should undergo a dehydration evacuation prior to recharging with refrigerant. As shown in the illustration, besides the vacuum pump suction manifold isolation valve being opened, what would be the proper valve positions to accomplish and prove the evacuation? Illustration GS-RA-51 Valves 1, 2, and 3 should be in the mid-position and the low-side gauge manifold hand valve should be closed, and the high-side gauge manifold hand valve should be open. Valves 1, 2, and 3 should be in the mid-position and the low-side gauge manifold hand valve should be open, and the high-side gauge manifold hand valve should be closed. Valves 1, 2, and 3 should be front-seated and both gauge manifold hand valves should be closed. Valves 1, 2, and 3 should be back-seated and both gauge manifold hand valves should be open. Refrigeration & Air Conditioning
B When a refrigeration system is being topped off with a small amount of refrigerant through the low side with the compressor running, what should be done? the refrigerant charging cylinder should be turned upside down the refrigerant should be charged into the system as a vapor the suction service valve must be back seated the discharge service valve must be front seated Refrigeration & Air Conditioning
C Which of the valves listed is normally closed when charging the refrigeration system through the high side? Thermal expansion valve Suction line valve Liquid line king valve Dehydrator inlet valve Refrigeration & Air Conditioning
A Using the device shown in the illustration, which of the following statements is true when adding refrigerant as a vapor to the low side of the refrigeration system __________. Illustration GS-RA-01 The hose labeled "H" should be connected to the suction service valve service port, the hose labeled "J" should be connected to the vapor valve on the refrigerant cylinder and the valve labeled "G" should be open. The hose labeled "K" should be connected to the suction service valve service port, the hose labeled "J" should be connected to the vapor valve on the refrigerant cylinder and the valve labeled "C" should be closed. The hose labeled "H" should be connected to the suction service valve service port, the hose labeled "J" should be connected to the vapor valve on the refrigerant cylinder and the valve labeled "G" should be closed. The hose labeled "K" should be connected to the suction service valve service port, the hose labeled "J" should be connected to the vapor valve on the refrigerant cylinder and the valve labeled "C" should be closed. Refrigeration & Air Conditioning
D What must be done, at a minimum, before a system can legally be opened up for repairs while adhering to the prohibition against the venting of halogenated fluoro-carbon refrigerants to the atmosphere? reclamation of the refrigerant destruction of the refrigerant recycling of the refrigerant recovery of the refrigerant Refrigeration & Air Conditioning
A The process of removing refrigerant from a system and storing it without testing or processing it in any way is known as what under the EPA Clean Air Act rule definitions? recovering recouping reclaiming recycling Refrigeration & Air Conditioning
C What is the correct color coding of refrigerant recovery cylinders regardless of the refrigerant contained within? gray top and light blue lower body gray top and yellow lower body yellow top and gray body light blue top and yellow lower body Refrigeration & Air Conditioning
C In reclaiming recovered refrigerant, which type of contamination will the reclamation process be unable to separate? moisture acid mixed refrigerants air Refrigeration & Air Conditioning
D In a refrigeration system, the push-pull technique can be used for the recovery of the refrigerant in what state? should never be used with low pressure systems liquid only vapor only both liquid and vapor Refrigeration & Air Conditioning
B Which recovery procedure should be used to minimize the loss of oil from the system during the recovery of refrigerant from small appliances such as a water cooler? vapor-liquid recovery vapor recovery liquid recovery initial recovery Refrigeration & Air Conditioning
A What is true concerning highly contaminated refrigerant recovered from burned out small appliances? The recovered refrigerant should be sent to a designated reclamation facility for processing. The recovered refrigerant may be blended with new refrigerant for eventual re-use. The recovered refrigerant may be used to clean out systems that have suffered from a burnout. The recovered refrigerant must be destroyed by the refrigeration technician. Refrigeration & Air Conditioning
C Technicians servicing small refrigeration appliances can employ what type of recovery equipment? passive only do not need to recover the refrigerant either active or passive active only Refrigeration & Air Conditioning
B Minor repairs may be performed on low pressure refrigerant systems without recovering the refrigerant charge if the pressure in the system is raised to atmospheric. How may this be accomplished? open the system vent to the atmosphere and allow the pressure to equalize heat the refrigerant pressurize the system with nitrogen charge the system until it is completely filled with liquid refrigerant Refrigeration & Air Conditioning
A Why is a purge recovery unit typically fitted on low pressure centrifugal chillers? such a chiller can operate at a pressure below atmospheric pressure on the low side thus drawing in air through any low-side leaks low pressure chillers are routinely opened for Maintenance thus introducing air at each opening low pressure chillers use extremely low boiling point refrigerants evacuation of the air from a low pressure chiller prior to charging with refrigerant is not possible Refrigeration & Air Conditioning
D The most cost-effective method of recovering refrigerant from a low pressure chiller with more than 500 lbs of refrigerant and to meet EPA requirements is to recover the refrigerant using what protocol? vapor recovery using a vacuum pump based recovery unit followed by liquid recovery using a liquid pump recovery using a vacuum pump based vapor recovery machine only recovering using a liquid pump only liquid recovery using a liquid pump, followed by vapor recovery using a vacuum pump based recovery unit Refrigeration & Air Conditioning
B As shown in the illustrated flow diagram for a self-contained recovery unit designed for the recovery of refrigerants from high pressure appliances as defined by the EPA Clean Air Act rules, what is the functional purpose of the item labeled "FS2"? Illustration GS-RA-32 It automatically shuts down the recovery unit compressor when the recovery cylinder becomes 80% full. It automatically transitions the recovery unit from the direct liquid recovery mode to the direct vapor recovery mode. It automatically shuts down the recovery unit compressor when the discharge pressure becomes excessive. It automatically shuts down the recovery unit compressor when the refrigeration system has reached a depth of 15" Hg. Refrigeration & Air Conditioning
B Some 'hot gas' defrost systems reheat the refrigerant just prior to its returning to the compressor for what purpose? to increase the circulation of liquid refrigerant to prevent the damaging effects of liquid slugging to improve the efficiency of the expansion valve to prevent chill shocking the compressor suction valves Refrigeration & Air Conditioning
A What is true concerning frost build-up on the evaporator coils of a multi-box direct expansion refrigeration system? the frost can be removed by passing hot gas through the coils or energizing defrost heaters with the evaporator fan shut down the frost can be removed by passing hot gas through the coils or energizing defrost heaters with the evaporator fan still running the frost can be quickly removed by simply shutting down the compressor the frost will increase the refrigeration effect Refrigeration & Air Conditioning
D Concerning frost appearing on one set of evaporator coils of a multi-box, direct expansion type refrigeration system, what is true? the frost can be quickly removed by simply shutting off fluid flow to the coils the frost will assist in increasing the refrigeration effect the frost will increase the value of superheat to the fluid leaving the coils the frost can be removed by passing hot vapors through the coils Refrigeration & Air Conditioning
C The pressure in the part of a high pressure refrigeration system about to be opened for a non-major repair should be brought to what value? 11 to 12 psig 4 to 7 psig 0 psig 1 to 2 psig Refrigeration & Air Conditioning
D What is the maximum volume to which refillable refrigeration cylinders should be filled? 90% full 60% full 70% full 80% full Refrigeration & Air Conditioning
C If the combination moisture indicator and sight glass indicates an accumulation of moisture within the system, which of the listed procedures would be the most practical to follow? Secure the system, disassemble and de-ice the thermostatic expansion valve. Using a vacuum pump, draw the entire system down to 1,270 microns for a period of three hours. Close the king valve, pump down the system, isolate the drier, remove the desiccant core and replace with new drier cartridge. Purge the entire system to the atmosphere, replace the drier cartridge, and recharge the system with refrigerant. Refrigeration & Air Conditioning
D If the discharge reed valves used in a refrigeration compressor are leaking badly, what statement is true? the reed valves should be reground and relapped the low side pressure will indicate below normal the high pressure cut-out setting should be lowered the reed valves should be replaced Refrigeration & Air Conditioning
C In addition to the drive belt itself, a V-belt that is tensioned too tight will cause excessive wear to what other drive component? the compressor drive pulley the prime mover drive pulley motor shaft and compressor main bearings the shaft of the prime mover Refrigeration & Air Conditioning
C When one belt of a multiple V-belt drive requires replacing, what will be required? ensure the seasoned belts are reinstalled in their proper sequence season the new belt prior to installation replace the entire belt set ensure the proper belt dressing is applied Refrigeration & Air Conditioning
D When installing a mechanical shaft seal on a refrigeration compressor, extreme care must be taken to prevent what from happening? any lubricant from contacting the carbon surface that would cause the expulsion of the saturated Teflon film any lubricant from contacting the stationary seal face that would cause etching of the face surface the spring from being damaged by the corrosive effects of excessive handling dirt and foreign particles from coming in contact with the highly polished sealing surfaces Refrigeration & Air Conditioning
B Excessively tight drive belts installed between a motor and a refrigeration compressor pulley may cause what condition? normal wear of the pulley end motor shaft bearing, but premature wear of the pulley end compressor crankshaft main bearing premature wear of both the pulley end motor shaft bearing and the pulley end compressor crankshaft main bearing due to overloading premature wear of the pulley end motor shaft bearing, but normal wear of the pulley end compressor crankshaft main bearing premature wear of both motor shaft bearings and both compressor crankshaft main bearings due to belt slippage Refrigeration & Air Conditioning
C The primary purpose of the liquid line strainer used in a refrigeration system is to prevent dirt and scale from entering what system component(s)? condenser and receiver evaporator coil piping thermal expansion valves compressor and oil separator Refrigeration & Air Conditioning
B Of the various possible methods shown in the illustration, which is the correct method of attaching a TXV feeler bulb to a small large line (7/8" and larger) with a horizontal run? Illustration GS-RA-50 A C D B Refrigeration & Air Conditioning
D A thermostatic expansion valve is properly controlling evaporator superheat. Adjusting this valve to lower the evaporator superheat setting will result in which of the following? the expansion valve will further close the expansion valve diaphragm will rupture the evaporator pressure will decrease the evaporator feed will increase Refrigeration & Air Conditioning
A When replacing a thermostatic expansion valve power element, what is true concerning the thermal bulb? with steel wool or an abrasive cloth remove oxidation on the bulb and suction line carefully coat the device with silicone sealant to reduce the effects of convective cooling apply a heavy coating of grease to function as a heat sink apply a light film of oil to increase heat transfer Refrigeration & Air Conditioning
A If the evaporator coil horizontal return line of a container refrigeration system is less than 0.875" (2.21 cm) in diameter (considered small); the thermostatic expansion valve sensing bulb should be attached where on the return line? on the upper surface of the line directly below the point of maximum heat transfer as close as possible to the expansion valve on the bottom of the line to enable the bulb to absorb the maximum amount of heat Refrigeration & Air Conditioning
A An evaporator coil of a single evaporator, air cooled refrigerator is accumulating excessive frost due to a failure of the defrost mechanism. If the refrigerator features a thermostatically controlled box solenoid and a low pressure cutout controlled compressor, as well as a high pressure cutout, in terms of the compressor, what would be the most likely operating symptom? short cycle on low pressure cutout fail to start short cycle on high pressure cutout run continuously Refrigeration & Air Conditioning
A If an abnormally large difference is maintained between the evaporator refrigerant temperature and the box air temperature within the refrigerated compartment, what will be the result? the evaporator coil will tend to excessively frost the box temperature will be pulled down too low the compressor will tend to trip out on high head pressure the compressor will tend to overheat due to high suction temperature Refrigeration & Air Conditioning
C Concerning the operation of refrigeration systems, frosting or sweating of a liquid line is usually indicative of what condition? high relative humidity surrounding the liquid line the refrigerant contaminated with moisture a liquid line restriction proper cooling taking place Refrigeration & Air Conditioning
C What is a quick method used to test a water cooled condenser for the presence of a refrigerant leak without actually pinpointing the actual location? test the cooling water for proper pH test the receiver for water content check the drains on the condenser heads with a halide torch test the condenser tubes hydrostatically Refrigeration & Air Conditioning
C What must be done to use standard leak detection methods on a low pressure refrigeration system charged with refrigerant? lower the pressure in the system below atmospheric add nitrogen to the system raise the pressure in the system above atmospheric cool the refrigerant Refrigeration & Air Conditioning
C What is the color of the flame produced by a halide torch when there is no halogenated refrigerant present at the location of the exploring tube? purple green blue orange Refrigeration & Air Conditioning
D Which of the following statements is correct concerning the testing of an R-22 refrigeration system for leaks in an enclosed compartment with a halide torch? Halide torches are not suitable for detecting R-22 leaks. The flame of a halide torch will turn blue in the presence of R-22. To gain sensitivity, the largest possible flame should be used with the halide torch. Halide torches are useful in locating very small R-22 leaks. Refrigeration & Air Conditioning
B To test for a suspected large refrigerant leak from an R-22 refrigeration system in an enclosed area, how should this be done? perform a hydrostatic test with water apply a soap solution to fittings seen to have oil residue perform a standing vacuum test use an electronic leak detector to check all fittings for leaks Refrigeration & Air Conditioning
C Excessive moisture being collected in the purge unit of a low pressure refrigeration system could indicate which probable condition? low efficiency purge unit dryer core needs replacement leaking condenser or chiller tubes improper charging of refrigerant Refrigeration & Air Conditioning
B Moisture entering a typical refrigeration system will most likely produce what effect? cause sweating and frost on the evaporator coils freeze in the expansion valve boil in the condenser be removed by the liquid line strainers Refrigeration & Air Conditioning
D Moisture in a refrigeration system can cause which of the following conditions? freezing the expansion valve closed corrosion of system piping hermetic motor burnout All of the above. Refrigeration & Air Conditioning
D High suction pressure accompanied by low suction temperature to a refrigeration system compressor is caused by which of the following? the king valve is insufficiently open the expansion valve is insufficiently opened a clogged liquid-line strainer the expansion valve being open too wide Refrigeration & Air Conditioning
B If a refrigeration system were short of refrigerant, besides an elevated box temperature, what would be an observable symptom? high suction pressure continuous running of the compressor short cycling of the compressor on the water failure switch high discharge pressure Refrigeration & Air Conditioning
A Which of the conditions listed could cause excessively low refrigerant pressure at the compressor suction of a TXV controlled refrigeration system? The system is low on refrigerant. The box solenoid valve 'stuck' in the open position. The high pressure cutout switch is inoperative. Insufficient flow of condenser cooling water. Refrigeration & Air Conditioning
C When a refrigeration compressor has developed a high head pressure as a result of a refrigerant overcharge, what should be done to compensate for or to correct this situation? increase the amount of cooling water to the condenser decrease the amount of cooling water to the condenser remove some refrigerant from the system raise the high pressure cut-out opening pressure Refrigeration & Air Conditioning
C Low compressor head pressure in a refrigeration system can be caused by which of the following? insufficient condenser cooling water flow air in the refrigeration system excessive condenser cooling water flow excessive refrigerant in the system Refrigeration & Air Conditioning
D Which of the following conditions will occur if the power element of the thermostatic expansion valve shown in the illustration loses its charge? Illustration GS-RA-07 The valve will begin to close, but the external equalizing line will assist in keeping the valve unseated. The valve will fail open and the cooling capacity will be increased. The valve will fail open as designed to provide continuous cooling. The valve will fail closed, providing no cooling capacity. Refrigeration & Air Conditioning
D Which of the following statements describes the accepted method for testing a thermostatic expansion valve? Chill the bulb in ice water while observing the compressor for an increase in suction pressure. Remove the power head from the unit, heat the bulb with a torch while using a scale to measure the distance the diaphragm has moved. Heat the bulb by using a halide torch or similar device and observe the valve stem movement. Place the sensing bulb in ice water and then warm by hand. Observe flood-through and temperature change at the suction line. Refrigeration & Air Conditioning
B If the superheat setting of a thermostatic expansion valve is set too low, what would be the result, assuming that the system has a single evaporator? the suction line will be abnormally warm due to a reduced amount of refrigerant returning back to the compressor the suction line will be abnormally cold and liquid may flood back to the compressor the receiver level will be abnormally high due to a reduced amount of refrigerant returning back to the compressor the box temperature will be pulled way down below the normal temperature range Refrigeration & Air Conditioning
A If the superheat value of the thermostatic expansion valve is adjusted too high, what would be the result? the suction line of the compressor will be abnormally warm the heat removal capacity of the evaporator will increase the evaporator will be overfed with liquid refrigerant the suction line of the compressor will be abnormally cold Refrigeration & Air Conditioning
A A small obstruction at the thermostatic expansion valve inlet will result in which of the following conditions? Lower than normal suction pressure. Ice is the sole cause of this and will soon melt due to superheat; no adverse condition will occur. Higher than normal discharge pressure. Expansion valves are designed to pass small foreign particles so no adverse condition will occur. Refrigeration & Air Conditioning
C You are checking the supply chilled water temperature thermistor probe on a high-pressure hermetic centrifugal chiller. Using the illustrated chart, what statement is true if the supply water temperature is verified 45 F with a digital thermometer? Illustration GS-RA-48 When checked with control power on and the thermistor probe isolated, the thermistor probe voltage drop should be 3.805 volts. When checked with control power on and the thermistor probe connected into the circuit, the thermistor probe voltage drop should be 11.416 volts. When checked with control power on and the thermistor probe connected into the circuit, the thermistor probe voltage drop should be 3.805 volts. When checked with control power off and the thermistor probe isolated, the thermistor probe voltage drop should be 3.805 volts. Refrigeration & Air Conditioning
B Some refrigeration systems have chemical moisture indicators installed in conjunction with the sight glass in the liquid line. If excess moisture is present in the system, how will a typical moisture indicator respond? add a predetermined amount of liquid drying agent change color automatically cut in the driers secure the compressor Refrigeration & Air Conditioning
D If the compressor is heard to knock while pumping down the low side for repairs, but otherwise the compressor sounds normal; this is a possible indication of what condition? worn piston rings faulty bearings air being introduced to the system foaming of the crankcase oil Refrigeration & Air Conditioning
D Excessive, prolonged oil foaming in the crankcase of a refrigeration compressor can result in what condition? wax crystals forming in the thermal expansion valve excessively high lube oil viscosity carbon deposits on the compressor piston rings overheated compressor bearings Refrigeration & Air Conditioning
A Which of the following conditions would indicate that the liquid line strainer in a refrigeration system has become excessively restricted and requires cleaning or replacement? Noticeable temperature drop between the strainer inlet and the outlet tubing. Frosting at the outlet of the receiver. Frosting at the inlet of the compressor. Excessively high suction pressure. Refrigeration & Air Conditioning
D Why are dehydrators usually located in the liquid line of refrigeration systems? prevent liquid slugging in the suction line reduce compressor discharge line sweating remove oil from the refrigerant prevent icing of the expansion valve Refrigeration & Air Conditioning
A Which of the devices listed will indicate whether or not a refrigeration system's dehydrator continues to be capable of removing moisture from the circulating refrigerant? Liquid line moisture indicating sight glass McLeod gage Dryer sensing bulb Particulate test Refrigeration & Air Conditioning
C In a refrigeration system, silica gel is found in what component? condenser/receiver compressor suction scale trap dehydrator or combination filter/drier moisture indicating liquid line sight glass Refrigeration & Air Conditioning
A If a liquid drying agent is used in a refrigeration system already equipped with a solid drying agent, the liquid drying agent will cause what type of reaction? it will release the moisture already trapped in the solid drying agent it will cause toxic gases to form in the refrigerated space it will react violently with the solid drying agent it will solidify the refrigerant oil in the compressor crankcase Refrigeration & Air Conditioning
C Standard filter/driers used in many commercial type refrigeration units may contain what type of substance? activated charcoal alcohol based liquid drying agents activated alumina or silica gel desiccant beads All of the above. Refrigeration & Air Conditioning
D Capacity control of a centrifugal refrigeration compressor can be accomplished by what means? varying the speed of the compressor varying the position of the suction inlet damper vanes varying the position of the hot gas bypass valve All of the above. Refrigeration & Air Conditioning
D The fluid used as a source of actuating power against the underside of the unloader power element piston of the refrigeration compressor capacity control mechanism illustrated is obtained from where? Illustration GS-RA-13 discharge of a secondary hydraulic pump specifically installed for this operation high side liquid receiver gas discharge from the compressor discharge of the compressor lube oil pump Refrigeration & Air Conditioning
C During operating periods of a multi-box refrigeration system using a capacity controlled compressor, when all of the evaporators of a four box plant are actively being fed with liquid refrigerant, the control oil pressure acting on the hydraulic relay piston will be at what value? Illustration GS-RA-13 the lowest at its mid-range the highest of no consequence as the lube oil is not used in the operation of the unloader Refrigeration & Air Conditioning
B A refrigeration compressor used in a multi-box refrigeration system is designed with six of its eight cylinders able to be controlled for variable load conditions. If all of the reefer boxes are currently feeding, what percentage of the total number of compressor cylinders will be loaded after start up? 50 (%) 100 (%) 25 (%) 0 (%) Refrigeration & Air Conditioning
A On a modern refrigerated container unit employing suction modulation for the purposes of capacity control and capacity limitation, what happens when the applied voltage and current draw associated with the normally open (NO) suction modulation valve located in the suction line both increase? the valve will further close, raising evaporator pressure and lowering suction pressure the valve will further close, lowering evaporator pressure and raising suction pressure the valve will further open, lowering evaporator pressure and raising suction pressure the valve will further open, raising evaporator pressure and lowering suction pressure Refrigeration & Air Conditioning
C To prevent motor overload during start-up of a hermetically sealed centrifugal refrigeration system, what is true concerning the compressor suction gas variable inlet guide vanes? opened until the motor is connected across the line at full voltage and current drawn is up to full load current opened until the motor is connected across the line at full voltage and current drawn is below full load current closed until the motor is connected across the line at full voltage and current drawn is below full load current closed until the motor is connected across the line at full voltage and current drawn is up to full load current Refrigeration & Air Conditioning
C A box solenoid valve used in a refrigeration system should be installed in what manner? upright, controlled by a thermostat sensing the temperature of the box, and downstream of the thermal expansion valve with the axis of the solenoid horizontal, controlled by a thermostat sensing the temperature of the box, and upstream of the thermal expansion valve upright, controlled by a thermostat sensing the temperature of the box, and upstream of the thermal expansion valve upright, controlled by a thermostat sensing evaporator superheat, and upstream of the thermal expansion valve Refrigeration & Air Conditioning
D In a multi-evaporator refrigeration system, a solenoid valve is installed in the liquid line prior to what device? the condenser the oil separator the receiver each expansion valve Refrigeration & Air Conditioning
B A liquid line solenoid valve controls refrigerant flow to the evaporator by what means? sensing the superheat in the tail coil fully opening or closing sensing the temperature in the liquid line throttling the refrigerant Refrigeration & Air Conditioning
D A box solenoid valve used in a multi-box refrigeration system is operated by electromagnetic action by what control device? evaporator outlet temperature actuated thermostat discharge pressure actuated pressure switch suction pressure actuated pressure switch box temperature actuated thermostat Refrigeration & Air Conditioning
D How does a refrigeration solenoid valve differ from a modulating valve? Both valves operate in exactly the same manner, only the manufacturer's terminology is the differentiating factor. A solenoid valve can only be installed in liquid lines. Solenoid Valves are only used in low voltage refrigeration control systems, while modulation valves are used in high voltage applications. A liquid line solenoid valve is either completely opened or closed, whereas a modulation valve is infinitely positioned according to the strength of the applied electrical signal. Refrigeration & Air Conditioning
C If it is necessary to increase the operating head pressure of the refrigeration system using the device shown in the illustration, what should be done? Illustration GS-RA-14 "4" should be rotated to compress the enclosed bellows "2" should be turned to relax the compression of the spring "2" should be turned to further compress the spring "4" should be rotated to relax the enclosed bellows Refrigeration & Air Conditioning
C In a refrigeration system that is not protected by a water failure switch, if the cooling water to the condenser fails, what will be the result for protective purposes? the king valve will open the box temperature solenoid valve will close initiating a pump down the compressor will shut down by the action of the high pressure cutout switch the expansion valve will close due to high superheat Refrigeration & Air Conditioning
A In a refrigeration system, the valve shown in the illustration is used for what purpose? Illustration GS-RA-14 head pressure regulating valve suction pressure regulating valve evaporator pressure regulating valve thermostatic expansion valve Refrigeration & Air Conditioning
D The set point adjustment of the device shown in the illustration is made by rotating what component? Illustration GS-RA-14 "4" "3" "1" "2" Refrigeration & Air Conditioning
B As shown in the illustrated refrigeration system piping schematic diagram with the various accessories and controls and equipped with an air-cooled condenser with high side pressure controls, what statement is true concerning the fan cycling control pressure switch? Illustration GS-RA-39 With a condenser fitted with a single fan driven by a single-speed electric motor, the fan would cycle off under high ambient temperature conditions. With a condenser fitted with a single fan driven by a multi-speed electric motor, the fan speed would decrease under low ambient temperature conditions. With a condenser fitted with multiple electric-motor driven fans, the number of fans in use would increase under low ambient temperature conditions. With a condenser fitted with a single fan driven by a multi-speed electric motor, the fan speed would decrease under high ambient temperature conditions. Refrigeration & Air Conditioning
B An arrow stamped on the valve body of a water regulating valve indicates which of the following? closed position direction of the flow open position direction of the plunger slide Refrigeration & Air Conditioning
B Through which of the components shown in the illustration is flash gas formation a normal occurrence? Illustration GS-RA-25 receiver tank thermostatic expansion valve evaporator coil condenser coil Refrigeration & Air Conditioning
C In the multi-evaporator refrigeration system shown in the illustration, what is the proper name for the valve labeled "29"? Illustration GS-RA-12 freeze box thermostatic expansion valve chill box evaporator pressure regulating valve chill box thermostatic expansion valve chill box solenoid valve Refrigeration & Air Conditioning
B Rather than design an infinite variety of thermostatic expansion valve sizes to accommodate different capacities for heat removal, some manufacturers use a few standard valve body sizes in conjunction with what other feature? an externally adjustable superheat to accommodate different heat removal capacities internal needle valve orifices of various sizes to accommodate different heat removal capacities a flexible diaphragm to accommodate different heat removal capacities internal equalizers to accommodate different heat removal capacities Refrigeration & Air Conditioning
A Constant superheat is maintained at the evaporator coil outlet of a refrigeration system or unit by the action of what device? thermal expansion valve low pressure cutout switch king valve solenoid valve Refrigeration & Air Conditioning
A Besides the evaporator pressure, the thermal expansion valve reacts directly to changes in what parameter? temperature of the evaporator coil outlet liquid refrigerant pressure at the solenoid valve pressure drop across the evaporator coils temperature of the space being cooled Refrigeration & Air Conditioning
A Refrigeration system isolation valves are specially designed with a back-seat, as well as a front-seat. For what purpose are these valves designed in this way? permit repacking the valve stem under pressure without shutting down allow for operation as a suction or discharge valve allow for operation as a liquid or vapor valve allow for removal and replacement of the valve without shutting down Refrigeration & Air Conditioning
D Which lettered component, shown in the illustration, indicates the location of the receiver? Illustration GS-RA-12 A B F C Refrigeration & Air Conditioning
B In a refrigeration plant, what is one vital purpose of the receiver? superheat the refrigerant liquid store the refrigerant charge condense the refrigerant cool the refrigerant gas Refrigeration & Air Conditioning
A In addition to the indicated gauge pressure, what other information is presented on the compound gauge for the hypothetical refrigerant illustrated? Illustration GS-RA-16 the saturation temperature of the refrigerant that corresponds to the gauge pressure at the point of measurement the metric pressure equivalent of the refrigerant at the point of measurement the absolute pressure of the refrigerant at the point of measurement the actual temperature of the refrigerant at the point of measurement Refrigeration & Air Conditioning
B The receiver used in a refrigeration system performs what essential function? allows the refrigerant to be superheated holds the entire refrigerant charge after system pump down prevents liquid refrigerant from flooding back to the compressor collects air and non-condensable gases Refrigeration & Air Conditioning
A During the initial cooling down of a box temperature in a refrigeration system, which of the devices listed is used to prevent excessive gas pressure at the compressor suction for the purpose of prevention of overloading of the compressor driver? Crankcase pressure regulator High pressure cutout Solenoid valve Low pressure cutout Refrigeration & Air Conditioning
B Which of the lettered components shown in the illustration indicates the high-pressure cut-out? Illustration GS-RA-12 Y X Z W Refrigeration & Air Conditioning
B The rupture disc on a low pressure centrifugal refrigeration unit is used as an over pressure protection device and is set to relieve at 15 psig and is most likely to lift when the compressor is idle? Where is the rupture disc located? at the top of the upper chamber of the economizer on top of chiller evaporator shell at the discharge of the compressor on top of the condenser shell Refrigeration & Air Conditioning
B When the relief valve opens on a refrigeration compressor discharge line, it discharges high pressure refrigerant vapor to what location? liquid strainer suction side of the compressor inlet side of the evaporator refrigerant inlet of the condenser Refrigeration & Air Conditioning
D The safety heads of most large reciprocating compressors used in refrigeration systems are held in place by what means? large Teflon gaskets tack welding on the sides discharge pressure in the relief valve return line heavy coil springs Refrigeration & Air Conditioning
D In the illustrated refrigeration system, what is the proper name for the component labeled "A"? Illustration GS-RA-12 condenser accumulator filter drier compressor Refrigeration & Air Conditioning
A What is the purpose of running a refrigeration compressor in short intermittent spurts or throttling the suction isolation valve when starting the system after a prolonged shutdown? prevent liquid slugging or overloading the compressor determine actual compressor oil level let the refrigerated compartment cool gradually allow refrigerant vapor cycling time Refrigeration & Air Conditioning
A A device used to hold open the refrigeration compressor suction valve during starting to reduce the compression load is called what? cylinder unloader discharge line bypass suction line bypass relief valve Refrigeration & Air Conditioning
B In a refrigeration system, what component is installed directly downstream of the thermal expansion valve? box solenoid valve evaporator coil receiver compressor Refrigeration & Air Conditioning
D Refrigeration systems using forced air circulation evaporators have a tendency to cause rapid dehydration of produce in chill boxes. Which of the following will minimize this dehydration? the air is circulated rapidly over a small evaporator with a minimum temperature differential the air is circulated rapidly over a small evaporator with a maximum temperature differential the air is circulated slowly over a large evaporator with a maximum temperature differential the air is circulated slowly over a large evaporator with a minimum temperature differential Refrigeration & Air Conditioning
B In a dry-type direct expansion refrigeration evaporator, what is true concerning the evaporator coils? the coils are surrounded on the outside by refrigerant the coils are surrounded on the outside by air the coils are covered on the outside with insulation the coils are coated on the inside with insulation Refrigeration & Air Conditioning
B If a condenser coil of an air-cooled container refrigeration system becomes dirty and requires cleaning, what would be an acceptable method of cleaning? Binks' gun with weak acid solvent high pressure water wash copper wire rotary brush All of the above. Refrigeration & Air Conditioning
B Zinc plates commonly found in refrigeration systems and used as sacrificial anodes are located where? cooling water suction strainer saltwater side of the condenser refrigerant side of the condenser evaporator coils Refrigeration & Air Conditioning
B Seawater or low temperature central fresh water is typically provided to a ship's stores refrigeration plant for what purpose? prevent motor overheating condense the refrigerant gas cool the expansion valve prevent refrigerant superheating Refrigeration & Air Conditioning
A Heat is removed from the refrigerant circulating through the refrigeration system, shown in the illustration, by which component? Illustration GS-RA-12 B A K J Refrigeration & Air Conditioning
C When checking zinc plates, or pencil Zincs in the refrigerating system condenser, what should you do? paint and insulate the plates to prevent corrosion file the plates to change the negative value replace the Zincs if deteriorated by 50% renew the plates at each inspection Refrigeration & Air Conditioning
A For safe storage, the maximum allowable temperature to which refrigerant bottles should be exposed is what temperature? 125F 100F 150F 175F Refrigeration & Air Conditioning
C Which of the precautions listed should be taken before opening any part of a refrigeration system for the purpose of accomplishing non-major repairs? Bring the part of the system to be opened to a pressure corresponding to the ambient temperature. Use the hot gas defrost line to remove any frost on the evaporator coils. Bring the part of the system to be opened to 0 psig. Set the high pressure cutout on manual to prevent automatic starting. Refrigeration & Air Conditioning
A Overfilling a refrigerant container is extremely dangerous because of the high pressures generated. The generation of pressure is the result of what? hydrostatic pressure of the expanding liquid vapor pressure of the refrigerant at saturation temperature discharge pressure from the recovery cylinder discharge pressure of the recovery compressor Refrigeration & Air Conditioning
D The FIRST thing to do to ensure that a refrigeration unit will not start while undergoing repairs is to do what? inform all persons in the area not to start the unit place a crow bar in the flywheel of the unit make a log book entry secure and tag the electrical circuit Refrigeration & Air Conditioning
B Personnel servicing refrigeration systems and subject to the exposure to commonly used refrigerants should wear what type of personal protective equipment? an all purpose gas mask goggles and gloves rubber soled shoes a respirator Refrigeration & Air Conditioning
D Inhalation of high concentrations of chlorofluorocarbon refrigerants (CFCs) may have which of the following effects? drowsiness loss of concentration cardiac arrhythmia's All of the above. Refrigeration & Air Conditioning
D In the presence of an open flame or hot surfaces, chlorinated fluorocarbon refrigerants decompose and form what chemical substance? water vapor petroleum crystals carbon monoxide phosgene gas Refrigeration & Air Conditioning
C If there is a "large" release of R-134a refrigerant gas in a confined area, which of the following statements would be true? safety goggles and lined butyl gloves would be required before entering the space an explosive atmosphere would be created a self-contained breathing apparatus (SCBA) would be required before entering the space dust or particle masks would be required before entering the space Refrigeration & Air Conditioning
A Why can CFC or HCFC refrigerants leaking into a confined space or in limited surroundings cause suffocation? Refrigerants are heavier than air and displace oxygen. Refrigerants lighter than air will rise. Refrigerants obnoxious odor prevents breathing. Refrigerants contain an acidic substance. Refrigeration & Air Conditioning
C When recovering R-12 from a small appliance with a working compressor, using a recovery device manufactured after November 15, 1993, what percentage of the remaining charge must be removed from the system? 75 (%) 99 (%) 90 (%) 80 (%) Refrigeration & Air Conditioning
A As shown in figure "B" of the illustrated self-contained recovery unit connection diagrams, what is the recovery method supported by the connection scheme? Illustration GS-RA-33 direct vapor recovery direct liquid recovery liquid recovery/push-pull vapor recovery/push-pull Refrigeration & Air Conditioning
B What must be done, at a minimum, before a system can legally be opened up for repairs while adhering to the prohibition against the venting of halogenated fluoro-carbon refrigerants to the atmosphere? destruction of the refrigerant recovery of the refrigerant reclamation of the refrigerant recycling of the refrigerant Refrigeration & Air Conditioning
B What is the correct color coding of refrigerant recovery cylinders regardless of the refrigerant contained within? light blue top and yellow lower body yellow top and gray body gray top and light blue lower body gray top and yellow lower body Refrigeration & Air Conditioning
B In a refrigeration system, the push-pull technique can be used for the recovery of the refrigerant in what state? vapor only both liquid and vapor should never be used with low pressure systems liquid only Refrigeration & Air Conditioning
C Which recovery procedure should be used to minimize the loss of oil from the system during the recovery of refrigerant from small appliances such as a water cooler? liquid recovery vapor-liquid recovery vapor recovery initial recovery Refrigeration & Air Conditioning
B What is true concerning highly contaminated refrigerant recovered from burned out small appliances? The recovered refrigerant may be used to clean out systems that have suffered from a burn

out.
The recovered refrigerant should be sent to a designated reclamation facility for processing. The recovered refrigerant may be blended with new refrigerant for eventual re-use. The recovered refrigerant must be destroyed by the refrigeration technician. Refrigeration & Air Conditioning
C Technicians servicing small refrigeration appliances can employ what type of recovery equipment? do not need to recover the refrigerant active only either active or passive passive only Refrigeration & Air Conditioning
A If passive recovery is used on a small appliance fitted with a capillary tube as a metering device with a non-operating compressor, the recovery should be made through what means? recovery from both the high and low sides by venting to atmosphere, cannot be recovered recovery from the high side only recovery from the low side only Refrigeration & Air Conditioning
B Minor repairs may be performed on low pressure refrigerant systems without recovering the refrigerant charge if the pressure in the system is raised to atmospheric. How may this be accomplished? pressurize the system with nitrogen heat the refrigerant open the system vent to the atmosphere and allow the pressure to equalize charge the system until it is completely filled with liquid refrigerant Refrigeration & Air Conditioning
C Why is a purge recovery unit typically fitted on low pressure centrifugal chillers? evacuation of the air from a low pressure chiller prior to charging with refrigerant is not
possible
low pressure chillers use extremely low boiling point refrigerants such a chiller can operate at a pressure below atmospheric pressure on the low side thus drawing in air through any low-side leaks low pressure chillers are routinely opened for maintenance thus introducing air at each opening Refrigeration & Air Conditioning
B The most cost-effective method of recovering refrigerant from a low pressure chiller with more than 500 lbs of refrigerant and to meet EPA requirements is to recover the refrigerant using what protocol? recovery using a vacuum pump based vapor recovery machine only liquid recovery using a liquid pump, followed by vapor recovery using a vacuum pump based recovery unit vapor recovery using a vacuum pump based recovery unit followed by liquid recovery using a liquid pump recovering using a liquid pump only Refrigeration & Air Conditioning
D As shown in the illustrated flow diagram for a self-contained recovery unit designed for the recovery of refrigerants from high pressure appliances as defined by the EPA Clean Air Act rules, what is the functional purpose of the item labeled "FS2"? Illustration GS-RA-32 It automatically shuts down the recovery unit compressor when the recovery cylinder becomes 80% full. It automatically shuts down the recovery unit compressor when the discharge pressure becomes excessive. It automatically shuts down the recovery unit compressor when the refrigeration system has reached a depth of 15" Hg. It automatically transitions the recovery unit from the direct liquid recovery mode to the direct vapor recovery mode. Refrigeration & Air Conditioning
D Traditionally, which of the listed refrigerants has been more suitable than the others for use in a centrifugal refrigeration compressor? R-12 Carbon dioxide Ammonia R-11 Refrigeration & Air Conditioning
C Which of the illustrated devices would be the LEAST accurate for the purposes of weighing-in a refrigerant charge? Illustration GS-RA-45 A B C D Refrigeration & Air Conditioning
B Before charging a refrigeration unit, unless quick disconnect fittings are used, the refrigerant charging hoses should be prepared in what way? they should be cleaned with carbon tetrachloride they should be purged with refrigerant they should be flushed with clean refrigerant oil they should be warmed in an oven Refrigeration & Air Conditioning
A Concerning the charging of refrigerant into a vapor compression refrigerating system, which of the following is true? when charging as a liquid it should be to the high side only when charging as a liquid it should be to the low side only when charging as a vapor it should be directly to the receiver only when charging as a liquid it may be to the low or high side Refrigeration & Air Conditioning
D The amount of HCFC-123 in a storage cylinder is measured by what means? volume saturation pressure saturation temperature weight Refrigeration & Air Conditioning
A Which of the illustrated valves is used to gain access to a hermetic system and features a Schrader core valve which is unseated by the core depressor of hose fitting when attached? Illustration GS-RA-69 D A B C Refrigeration & Air Conditioning
B How should small appliances with less than three pounds of refrigerant be charged with refrigerant? initially liquid charged and then topped with a vapor charge vapor charged either vapor or liquid charged liquid charged Refrigeration & Air Conditioning
C Charging liquid HCFC-123 into a system under a deep vacuum could cause what to happen unless necessary precautions are taken? the purge unit to operate air and moisture to enter the receiver system secondary refrigerant to freeze rupture disk to rupture Refrigeration & Air Conditioning
A When a refrigeration system is being topped off with a small amount of refrigerant through the low side with the compressor running, what should be done? the refrigerant should be charged into the system as a vapor the refrigerant charging cylinder should be turned upside down the discharge service valve must be front seated the suction service valve must be back seated Refrigeration & Air Conditioning
A Which of the valves listed is normally closed when charging the refrigeration system through the high side? Liquid line king valve Dehydrator inlet valve Suction line valve Thermal expansion valve Refrigeration & Air Conditioning
D Using the device shown in the illustration, which of the following statements is true when adding refrigerant as a vapor to the low side of the refrigeration system __________. Illustration GS-RA-01 The hose labeled "K" should be connected to the suction service valve service port, the hose labeled "J" should be connected to the vapor valve on the refrigerant cylinder and the valve labeled "C" should be closed. The hose labeled "K" should be connected to the suction service valve service port, the hose labeled "J" should be connected to the vapor valve on the refrigerant cylinder and the valve labeled "C" should be open. The hose labeled "H" should be connected to the suction service valve service port, the hose labeled "J" should be connected to the vapor valve on the refrigerant cylinder and the valve labeled "G" should be closed. The hose labeled "H" should be connected to the suction service valve service port, the hose labeled "J" should be connected to the vapor valve on the refrigerant cylinder and the valve labeled "G" should be open. Refrigeration & Air Conditioning
C Which of the fluids listed is suitable for use as a secondary refrigerant? Carbon dioxide Methyl alcohol Brine Cuprous chloride Refrigeration & Air Conditioning
A According to 46 CFR, Part 58, for protection purposes, what is required of all refrigeration systems? pressure relief device refrigerant receiver low pressure cut-out high pressure cut-out Refrigeration & Air Conditioning
C With regards to shipboard refrigeration systems, after July 1, 1992, what action became illegal? working on a refrigeration system without permission of the Officer in Charge Marine
Inspection
mixing R-12 and R-22 intentionally venting class I or II refrigerants to the atmosphere producing a class I refrigerant Refrigeration & Air Conditioning
B Refillable tanks used to ship CFC and HCFC refrigerants or used to recover these refrigerants must meet the standards of what entity? the United States Coast Guard the United States Department of Transportation the Underwriters Laboratories the Environmental Protection Agency Refrigeration & Air Conditioning
B Coast Guard Regulations (46 CFR Part 58) require a method for the relieving pressure of an over pressurized refrigeration system. Which of the following statements complies with these Regulations? The rupture disk shall burst at a pressure not higher than 10% above the relief valve setting. A rupture disk may be fitted in series with the relief valve. The relief valve settings shall be 1 1/4 times the maximum allowable working pressure. The relief valve from the receiver must relieve to the condenser first. Refrigeration & Air Conditioning
D Coast Guard Regulations (46 CFR Part 113) require refrigerated spaces that can be locked from the outside and that cannot be opened from the inside to have an audible alarm. Where is the audible alarm required to be? the wheelhouse the galley the chief steward's berthing quarters a manned location Refrigeration & Air Conditioning
A What would be an example of a small appliance as defined in the EPA Clean Air Act rules? a hermetically sealed water cooler with a 2 lb. refrigerant charge a 200 ton low pressure centrifugal chiller for cargo hold air conditioning a 25 ton air conditioning system set up as a split plant with the condensing unit on deck a self-contained walk-in freezer with a 60 lbs. refrigerant charge Refrigeration & Air Conditioning
B Within the territorial limits of the United States, violations of the Clean Air Act of 1990, that includes the intentional release of R-11, R-12, R-22 and other related class I or class II substances may result in fines for each violation per day of what amount? $50,000 $25,000 $5,000 $10,000 Refrigeration & Air Conditioning
C All shipboard personnel responsible for the maintenance and repair of air conditioning systems using refrigerants covered under the EPA Clean Air Act venting prohibition, must be certified through an approved Environmental Protection Agency (EPA) program to do which of the following? before they can pump down the system in preparation for shifting over to the standby
condensing unit
before they can set the operating controls of the system before performing Maintenance, service or repair that could reasonably be expected to release Class 1 or Class 2 refrigerants into the atmosphere before performing any Maintenance or repair regardless of the actual procedure Refrigeration & Air Conditioning
A EPA Clean Air Act rules permit refrigerant to be released to the atmosphere under which of the following conditions? when release is considered 'de minimis' during replacement of a compressor when adding oil to a compressor when testing a system for leaks using R-12 and nitrogen Refrigeration & Air Conditioning
C Persons recovering refrigerant from small appliances must be certified as what type of technician under the EPA Clean Air Act rules? Type II technician Type III technician Type I or Universal technician All of the above. Refrigeration & Air Conditioning
C According to the EPA Clean Air Act rules, what is true concerning refrigerant leaks in a small hermetically sealed shipboard water cooler with a 20 ounce charge weight? The leaks must be repaired if the annual leak rate exceeds 15% of the total charge The leaks must be repaired if the annual leak rate exceeds 35% of the total charge. Legally, the leaks are not required to be repaired, but morally it is advisable to repair the leaks. The leaks must be repaired within 30 days. Refrigeration & Air Conditioning
C If you find the pressure of a refrigeration system containing a Class I or Class II refrigerant to be opened for the accomplishment of repairs is 0 psig, what must be done? recover liquid and vapor refrigerant and have it reclaimed only recover the liquid refrigerant in the system do not attempt to recover the refrigerant and repair the leak before pulling a vacuum on the system only recover the vapor refrigerant Refrigeration & Air Conditioning
A Which best defines a "Type I" small refrigeration appliance according to the EPA Regulations Section 608? systems manufactured and hermetically sealed having a capacity of five pounds (2.27 kg) or less of refrigerant any appliance charged with less than ten pounds (4.54 kg) of refrigerant refrigerators, freezers, room air conditioners and central air conditioners any appliance charged with less than two pounds (0.91 kg) of refrigerant Refrigeration & Air Conditioning
C Alkylbenzene ISO 32 cSt synthetic refrigerant oil is miscible and suitable to use with which of the following refrigerants? R-32 R-143a R-22 R-134a Refrigeration & Air Conditioning
B For safe storage, the maximum allowable temperature to which refrigerant bottles should be exposed is what temperature? 150F 125F 100F 175F Refrigeration & Air Conditioning
A Overfilling a refrigerant container is extremely dangerous because of the high pressures generated. The generation of pressure is the result of what? hydrostatic pressure of the expanding liquid discharge pressure from the recovery cylinder discharge pressure of the recovery compressor vapor pressure of the refrigerant at saturation temperature Refrigeration & Air Conditioning
D Personnel servicing refrigeration systems and subject to the exposure to commonly used refrigerants should wear what type of personal protective equipment? rubber soled shoes a respirator an all purpose gas mask goggles and gloves Refrigeration & Air Conditioning
A In the presence of an open flame or hot surfaces, chlorinated fluorocarbon refrigerants decompose and form what chemical substance? phosgene gas carbon monoxide water vapor petroleum crystals Refrigeration & Air Conditioning
A Why can CFC or HCFC refrigerants leaking into a confined space or in limited surroundings cause suffocation? Refrigerants are heavier than air and displace oxygen. Refrigerants lighter than air will rise. Refrigerants obnoxious odor prevents breathing. Refrigerants contain an acidic substance. Refrigeration & Air Conditioning
C The amount of HCFC-123 in a storage cylinder is measured by what means? saturation pressure volume weight saturation temperature Refrigeration & Air Conditioning
A Which of the following statements is true concerning the gauge labeled "A" of the illustrated gauge manifold set? Illustration GS-RA-01 The gauge labeled "A" is a compound gauge and is usually color-coded blue. The gauge labeled "A" is a compound gauge and is usually color-coded red. The gauge labeled "A" is a standard pressure gauge and is usually color-coded blue. The gauge labeled "A" is a standard pressure gauge and is usually color-coded red. Refrigeration & Air Conditioning
D Which of the following statements is true concerning the illustrated gauge manifold set? Illustration GS-RA-01 The valves labeled "G" and "C" must both be open to read system pressures on the
respective gages labeled "A" and "B".
Closing the valve labeled "G" isolates the hose labeled "H" from the gauge labeled "A". Opening fully and back seating the valve labeled "G" isolates the gauge labeled "A" from the


hose labeled "H".
Closing the valve labeled "G" isolates the hose labeled "H" from the hose labeled "J". Refrigeration & Air Conditioning
A When repairing a refrigeration system, a swaging tool set would be used to carry out which of the following operations? Swaging tools can be used to expand an end of one tube to fit onto a tube of the same original outside diameter. Swaging tools are used to remove any sweated edges formed on the tubing while soldering. Swaging tools are used during the breaking-in of refrigeration compressors and drive motors. Swaging tools are no longer used with repairing refrigeration systems due to progressive changes in the tool industry. Refrigeration & Air Conditioning
B Which of the illustrated gauges is capable of measuring vacuums at the micron level for the purpose of proving system dehydration during system evacuation with a vacuum pump, but displays the achieved vacuums at incremental threshold intervals rather than continuously. Illustration GS-RA-37 A B C D Refrigeration & Air Conditioning
A Which of the following substances is normally classified as a low pressure refrigerant? R-123 R-22 R-12 R-134A Refrigeration & Air Conditioning
A What is the purpose of running a refrigeration compressor in short intermittent spurts or throttling the suction isolation valve when starting the system after a prolonged shutdown? prevent liquid slugging or overloading the compressor allow refrigerant vapor cycling time let the refrigerated compartment cool gradually determine actual compressor oil level Refrigeration & Air Conditioning
B When starting a reciprocating refrigeration compressor that has been shut down for a period of time, you should manually throttle which valve? king valve suction valve expansion valve sea water valve Refrigeration & Air Conditioning
A When opening or closing compressor service and line isolation valves on a typical refrigeration system that is fitted with packed valves, what must you do? you must first remove the stem seal cap you should replace the gasket each time the valve position is changed you should never loosen or tighten the packing gland you should turn valves slowly to avoid thermal stresses due to low temperatures Refrigeration & Air Conditioning
C What is the color coding for a storage container of R-134a refrigerant? green purple light blue grey Refrigeration & Air Conditioning
B The gas that exists in the stratosphere forming a protective shield that helps to protect the environment from the harmful effects ultraviolet radiation is called what? radon ozone oxygen nitrogen Refrigeration & Air Conditioning
A In an air conditioning system, what is the name of the chamber where the duct-work originates? plenum chamber exhaust chamber vapor chamber intake chamber Refrigeration & Air Conditioning
B In a two stage centrifugal air conditioning system, the liquid refrigerant passes through the condenser directly to what component? expansion valve economizer chiller evaporator Refrigeration & Air Conditioning
A A reheater in an air conditioning system performs what function? restores the conditioned air temperature to a comfortable level controls the inlet air volume controls the inlet air temperature maintains the relative humidity at 15% Refrigeration & Air Conditioning
D What is one benefit of Maintenance of proper air circulation in an air conditioned cargo space? more temperature differential increased moisture content increased density of the air reduced slime and mold Refrigeration & Air Conditioning
A What is the wet bulb temperature of air if the dry bulb temperature of the air is 90 degrees and the relative humidity is 65%? Illustration GS-RA-22 80 degrees F 63 degrees F 77 degrees F 62 degrees F Refrigeration & Air Conditioning
B In general, the thermal bulb for a thermal expansion valve used in a reciprocating air conditioning system is usually charged with what substance? bees wax the same refrigerant as the system mercuric sulfate distilled water Refrigeration & Air Conditioning
D To prevent the unnecessary loading of an air conditioning system while maintaining the designed dry bulb temperature and relative humidity in an air conditioning system, what should be done? operate the purge recovery unit continuously reduce the air reheating system load lower the compressor head pressure admit only enough fresh outside air to provide proper ventilation Refrigeration & Air Conditioning
D Which of the following is true concerning the class "D" air conditioning system shown in the following illustration? Illustration GS-RA-42 The heat load will increase by increasing the amount of recirculated air. The room thermostat controls the wet bulb temperature of the air conditioned space. System cooling is the direct result of the Freon circuit of a direct type air conditioning unit. The duct thermostat determines the amount of water flow circulating through the cooling coil. Refrigeration & Air Conditioning
A Concerning the arrangement of equipment and associated hoses shown in the illustration, what statement is true? Illustration GS-RA-59 When recovering refrigerant from the centrifugal chiller using this method, it is possible to achieve the recovery levels required by law without any further recovery. When recovering refrigerant from the centrifugal chiller using this method, the refrigerant is being recovered as a liquid. When recovering refrigerant from the centrifugal chiller using this method, the containment tank should be vented back to the chiller evaporator shell. When recovering refrigerant from the centrifugal chiller using this method, the entire charge may be removed in one procedure. Refrigeration & Air Conditioning
B Which of the following methods is normally used to control the circulated air temperature of an air conditioning system using chilled water circulation? A fan speed controller regulates the amount of air flowing across the coils. A regulating valve controls the quantity of chilled water flowing in the cooling coils. A regulating valve changes the inlet temperature of the water in the cooling coils. Control dampers varying the number of passes the air makes across the cooling coils. Refrigeration & Air Conditioning
D For the proper control of the air temperature in an air conditioning system using chilled water circulation, which of the listed conditions should remain constant regardless of load changes? Compressor discharge temperature. Chilled water system return temperature. Compressor suction pressure. Chilled water system supply temperature. Refrigeration & Air Conditioning
C Which of the processes listed would be the most satisfactory method to use to lower the humidity of the air being circulated by an air conditioning system? Cooling the air to a temperature just above dew point. Heating the air and then cooling it to a point below dew point. Cooling the air to a point below dew point, then reheating it. Heating the air to a point at which moisture will boil off, then recooling it. Refrigeration & Air Conditioning
C A room humidistat initiates the lowering of the humidity of the conditioned supply air to a space, while the actual process is accomplished by what means? raising the cooling coil temperature and lowering the reheater temperature raising both the cooling coil temperature and the reheater temperature lowering the cooling coil temperature and raising the reheater temperature lowering both the cooling coil temperature and the reheater temperature Refrigeration & Air Conditioning
D In an air conditioning system, moisture is removed from the air by what means? separators ducted traps filters cooling coils Refrigeration & Air Conditioning
A The introduction of outside air to the air conditioning system is 90F with a relative humidity of 60%. The air has been conditioned to 70F with a relative humidity of 80%. Using the psychrometric chart, shown in the illustration, determine the quantity of moisture removed from one pound of the conditioned air __________. Illustration GS-RA-22 40 grains 50 grains 30 grains 20 grains Refrigeration & Air Conditioning
B If outside air at 80 degrees F and 70 percent relative humidity is conditioned, what will be the resulting dew point temperature of the air just before it comes into contact with the cooling coil? Illustration GS-RA-22 64 degrees F 70 degrees F 73 degrees F 67 degrees F Refrigeration & Air Conditioning
C Which of the following is true concerning the class "A" air conditioning system shown in the illustration as used to condition the air of large public spaces? Illustration GS-RA-09 The reheater is not used when in the cooling mode. The preheater steam flow is controlled by the space thermostat. The dry bulb room temperature is controlled by a steam heated reheater and its associated pneumatic control valve. Illustration GS-RA-09 It is not possible for both the cooling coil and the steam heated reheater to be used
simultaneously.
Refrigeration & Air Conditioning
A To add small amounts of refrigerant to the low side of an air conditioning system, the refrigerant should be introduced through a particular valve and in a particular state. What valve and state combination is correct? suction service valve as a vapor discharge service valve as a liquid discharge service valve as a vapor suction service valve as a liquid Refrigeration & Air Conditioning
D To add refrigerant to the high side of an air conditioning system, you should close the king valve and introduce the refrigerant through what valve in what state? condenser purge valve as a vapor suction service valve as a liquid discharge service valve as a vapor charging valve as a liquid Refrigeration & Air Conditioning
C When pumping down an air conditioning system to test the low-pressure cut-out switch, assuming that the compressor is running, what should be done to initiate the test? secure the condenser stop the compressor close the 'king' valve stop the circulating pump Refrigeration & Air Conditioning
C When recovering the remaining R-134a refrigerant from the centrifugal chiller shown in the illustration as a vapor using the recovery unit's compressor, in addition to opening valves "1a", "1b", and the compressor suction and discharge isolation valves, which of the following would be the correct valve lineup? Illustration GS-RA-28 valves "3", "5", and "6" open; valves "2", "4", "7", "8", and "10" closed valves "3", "4", "7", "6" and "10" open; valves "2", "5", and "8" closed valves "3", "4", and "6" open; valves "2", "5", "7", "8", and "10" closed valves "2", "5", "7", "8", and "10" open; valves "3", "4", and "6" closed Refrigeration & Air Conditioning
B The compressor used in a water-cooled air conditioning system is short cycling. A service check determines that the suction pressure remains above the normal cut-in point during cycling and that the discharge pressure rapidly builds up to the cut-out point while running and gradually falls to the cut-in point during the off cycle. What is likely the cause? back seated discharge service valve reduction in condenser water flow (scaled condenser) loosely fitted compressor drive belt front seated liquid line service valve Refrigeration & Air Conditioning
D Using the illustrated chart giving the boiling point of moisture at various depths of vacuum, with an ambient temperature of 72 F, what depth of vacuum would be associated with the BEST chance of achieving a dehydration evacuation with a deep vacuum pump? Illustration GS-RA-56 29" Hg gauge or 25,400 microns of Hg absolute 28.75" Hg gauge or 31,750 microns of Hg absolute 29.20" Hg or 20,320 microns of Hg absolute 29.99" Hg or 254 microns of Hg absolute Refrigeration & Air Conditioning
B Concerning the arrangement of equipment and associated hoses shown in the illustration, what statement is true? Illustration GS-RA-58 When recovering refrigerant from the centrifugal chiller using this method, it is permissible to exceed 90% of the weight capacity of the refrigerant drum. When recovering refrigerant from the centrifugal chiller using this method, it minimizes the risk of chiller tube freeze-up When recovering refrigerant from the centrifugal chiller using this method, it is possible to achieve the recovery levels required by law without any further recovery. When recovering refrigerant from the centrifugal chiller using this method, the vent hose connection should be closed. Refrigeration & Air Conditioning
A The surging that occurs in a centrifugal air conditioning compressor is a result of what conditions? low pressure in the evaporator at low load low pressure in the condenser at low load low pressure in the condenser at high load low pressure in the evaporator at high load Refrigeration & Air Conditioning
C In an air conditioning system, low discharge head pressure associated with a reciprocating compressor can be the result of what condition? insufficient cooling water to the condenser air in the evaporator coils leaky suction valves air in the condenser Refrigeration & Air Conditioning
A The air temperature associated with a direct reciprocating air conditioning plant is found to be too warm, and the compressor is not operating. A service check determines the compressor suction pressure to be above the normal cut-in point, with a normal head pressure, and high evaporator superheat. Which of the following could be the cause of this problem? The low pressure control contacts are stuck open. A liquid line solenoid valve has failed closed. Cooling water flow to the condenser is excessive. A liquid line solenoid valve is stuck open. Refrigeration & Air Conditioning
A Sludge may form in the crankcase of an air conditioning compressor as a result of what condition? overheating and carbonization of the oil in the crankcase reducing the cloud or floc point of the oil lowered compressor operating temperatures excessive foaming of the oil in the crankcase Refrigeration & Air Conditioning
A As shown in the illustrated LP centrifugal chiller high efficiency purge recovery unit piping schematic, what statement is true concerning the vacuum pump? Illustration GS-RA-55 The vacuum pump is designed to remove refrigerant vapor from the carbon filter tank and transfer these vapors to the evaporator to minimize the loss of refrigerant to the atmosphere. The vacuum pump is designed to remove refrigerant vapor from the carbon filter tank and transfer these vapors to the purge chamber to blow the float valve clear. Illustration GS-RA-55 The vacuum pump is designed to remove air and non-condensable gases from the evaporator and transfer these gases to the carbon filter tank for eventual venting to the atmosphere. The vacuum pump is designed to perform a dehydration evacuation on the system prior to charging with refrigerant. Refrigeration & Air Conditioning
B The "tare weight" of a refrigerant storage cylinder refers to what weight? the total weight of a fully charged cylinder the weight of an empty cylinder the weight of a cylinder AND its current contents the maximum weight of the refrigerant allowed Refrigeration & Air Conditioning
A The term 'oil foaming' in refrigeration practice, is used to describe what event? release of miscible refrigerant from the lubricant in the crankcase release of dissolved lubricant from the refrigerant in the crankcase sudden evaporation of entrapped moisture from the crankcase lubricant sudden evaporation of entrapped air from the refrigerant liquid Refrigeration & Air Conditioning
C What is the physical state and pressure condition of refrigerant as it enters the condenser of a typical refrigeration system? low pressure vapor low pressure liquid high pressure vapor high pressure liquid Refrigeration & Air Conditioning
B What is the physical state and pressure condition of refrigerant as it leaves a receiver in a typical refrigeration system? high pressure vapor high pressure liquid low pressure vapor low pressure liquid Refrigeration & Air Conditioning
D What is the pressure and condition of the refrigerant entering the receiver of a refrigeration system? superheated low pressure vapor superheated high pressure vapor sub cooled low pressure liquid sub cooled high pressure liquid Refrigeration & Air Conditioning
B The safety heads of most large reciprocating compressors used in refrigeration systems are held in place by what means? tack welding on the sides heavy coil springs discharge pressure in the relief valve return line large Teflon gaskets Refrigeration & Air Conditioning
B In the illustrated refrigeration system, what is the proper name for the component labeled "A"? Illustration GS-RA-12 accumulator compressor condenser filter drier Refrigeration & Air Conditioning
A A device used to hold open the refrigeration compressor suction valve during starting to reduce the compression load is called what? cylinder unloader relief valve suction line bypass discharge line bypass Refrigeration & Air Conditioning
C The carbon seal ring of a refrigeration compressor crankshaft mechanical seal is held in position against the stationary ring face by using what device? snap ring woodruff key spring thrust washer Refrigeration & Air Conditioning
A What is the drive arrangement of refrigeration compressor shown in figure "B" of the illustration? Illustration GS-RA-41 welded, fully hermetic external-drive open serviceable, bolted, accessible semi-hermetic Refrigeration & Air Conditioning
B If the discharge reed valves used in a refrigeration compressor are leaking badly, what statement is true? the reed valves should be reground and relapped the reed valves should be replaced the low side pressure will indicate below normal the high pressure cut-out setting should be lowered Refrigeration & Air Conditioning
B In addition to the drive belt itself, a V-belt that is tensioned too tight will cause excessive wear to what other drive component? the compressor drive pulley motor shaft and compressor main bearings the shaft of the prime mover the prime mover drive pulley Refrigeration & Air Conditioning
B When one belt of a multiple V-belt drive requires replacing, what will be required? ensure the proper belt dressing is applied replace the entire belt set season the new belt prior to installation ensure the seasoned belts are reinstalled in their proper sequence Refrigeration & Air Conditioning
A When installing a mechanical shaft seal on a refrigeration compressor, extreme care must be taken to prevent what from happening? dirt and foreign particles from coming in contact with the highly polished sealing surfaces any lubricant from contacting the carbon surface that would cause the expulsion of the saturated Teflon film any lubricant from contacting the stationary seal face that would cause etching of the face surface the spring from being damaged by the corrosive effects of excessive handling Refrigeration & Air Conditioning
C Excessively tight drive belts installed between a motor and a refrigeration compressor pulley may cause what condition? premature wear of the pulley end motor shaft bearing, but normal wear of the pulley end compressor crankshaft main bearing premature wear of both motor shaft bearings and both compressor crankshaft main bearings due to belt slippage premature wear of both the pulley end motor shaft bearing and the pulley end compressor crankshaft main bearing due to overloading normal wear of the pulley end motor shaft bearing, but premature wear of the pulley end compressor crankshaft main bearing Refrigeration & Air Conditioning
B Which of the listed statements describes the reason why oil foaming occurs when starting a refrigeration compressor? This phenomenon is inherent only in hermetically sealed units and is always provisional. This condition is the result of the sudden low pressure created in the crankcase at start up causing the release of refrigerant absorbed within the oil. If the oil level is not initially high, this condition is the result of agitation created by the movement of the mechanical components. This will occur only if crankcase heaters are used. Refrigeration & Air Conditioning
C A reciprocating refrigeration compressor may be tested for leaking discharge valves by stopping the compressor, turning the discharge service valve all the way in, and then turning the compressor over by hand. If the discharge valves are leaking, the compound gage will show pressures which react in which way? decreasing to a vacuum increasing with each stroke rising and falling with each stroke decreasing with each stroke Refrigeration & Air Conditioning
D Unusual noise coming from a refrigeration compressor can be caused by which of the following conditions? worn bearings and piston pins slugging due to flooding back too much oil in circulation All of the above. Refrigeration & Air Conditioning
B Leaking suction valves in a refrigeration compressor are indicated by which of the following? noticeable increase in compressor noise higher than normal suction pressure lower than normal suction pressure lower than normal evaporator temperature Refrigeration & Air Conditioning
B For most multi-box refrigeration systems, the refrigerant sight glass would be located where in the system? after the condenser in the drain line to the receiver after the receiver in the liquid line before the compressor in the suction line after the compressor in the discharge line Refrigeration & Air Conditioning
C Which of the following dehydrators or combination filter/driers features a core that can be replaced when the desiccant becomes saturated with moisture? Illustration GS-RA-10 B D A C Refrigeration & Air Conditioning
B A liquid indicator sight glass is useful in determining whether or not a refrigeration system is sufficiently charged. Where is it generally located in the system? low pressure liquid line high pressure liquid line low pressure vapor line high pressure vapor line Refrigeration & Air Conditioning
B Why are dehydrators usually located in the liquid line of refrigeration systems? reduce compressor discharge line sweating prevent icing of the expansion valve prevent liquid slugging in the suction line remove oil from the refrigerant Refrigeration & Air Conditioning
D Which of the devices listed will indicate whether or not a refrigeration system's dehydrator continues to be capable of removing moisture from the circulating refrigerant? Particulate test McLeod gage Dryer sensing bulb Liquid line moisture indicating sight glass Refrigeration & Air Conditioning
A In a refrigeration system, silica gel is found in what component? dehydrator or combination filter/drier condenser/receiver moisture indicating liquid line sight glass compressor suction scale trap Refrigeration & Air Conditioning
A The device shown in the illustration which is used for removing moisture from the liquid refrigerant in the system is labeled with what letter? Illustration GS-RA-12 E C B D Refrigeration & Air Conditioning
C If a liquid drying agent is used in a refrigeration system already equipped with a solid drying agent, the liquid drying agent will cause what type of reaction? it will solidify the refrigerant oil in the compressor crankcase it will cause toxic gases to form in the refrigerated space it will release the moisture already trapped in the solid drying agent it will react violently with the solid drying agent Refrigeration & Air Conditioning
A Moisture is removed from a refrigeration system by what action? cutting in the dehydrator condensing the water in the heat exchanger draining refrigerant from the bottom of the condenser opening a drain petcock on the oil separator Refrigeration & Air Conditioning
C Standard filter/driers used in many commercial type refrigeration units may contain what type of substance? activated charcoal alcohol based liquid drying agents activated alumina or silica gel desiccant beads All of the above. Refrigeration & Air Conditioning
B The primary purpose of the liquid line strainer used in a refrigeration system is to prevent dirt and scale from entering what system component(s)? evaporator coil piping thermal expansion valves compressor and oil separator condenser and receiver Refrigeration & Air Conditioning
B On a modern refrigerated container unit employing suction modulation for the purposes of capacity control and capacity limitation, what happens when the applied voltage and current draw associated with the normally open (NO) suction modulation valve located in the suction line both increase? the valve will further close, lowering evaporator pressure and raising suction pressure the valve will further close, raising evaporator pressure and lowering suction pressure the valve will further open, lowering evaporator pressure and raising suction pressure the valve will further open, raising evaporator pressure and lowering suction pressure Refrigeration & Air Conditioning
D To prevent motor overload during start-up of a hermetically sealed centrifugal refrigeration system, what is true concerning the compressor suction gas variable inlet guide vanes? opened until the motor is connected across the line at full voltage and current drawn is up to full load current opened until the motor is connected across the line at full voltage and current drawn is below full load current closed until the motor is connected across the line at full voltage and current drawn is up to full load current closed until the motor is connected across the line at full voltage and current drawn is below full load current Refrigeration & Air Conditioning
D Capacity control of a centrifugal refrigeration compressor can be accomplished by what means? varying the speed of the compressor varying the position of the suction inlet damper vanes varying the position of the hot gas bypass valve All of the above. Refrigeration & Air Conditioning
A The fluid used as a source of actuating power against the underside of the unloader power element piston of the refrigeration compressor capacity control mechanism illustrated is obtained from where? Illustration GS-RA-13 discharge of the compressor lube oil pump gas discharge from the compressor high side liquid receiver discharge of a secondary hydraulic pump specifically installed for this operation Refrigeration & Air Conditioning
C During operating periods of a multi-box refrigeration system using a capacity controlled compressor, when all of the evaporators of a four box plant are actively being fed with liquid refrigerant, the control oil pressure acting on the hydraulic relay piston will be at what value? the lowest at its mid-range the highest of no consequence as the lube oil is not used in the operation of the unloader Refrigeration & Air Conditioning
B A refrigeration compressor used in a multi-box refrigeration system is designed with six of its eight cylinders able to be controlled for variable load conditions. If all of the reefer boxes are currently feeding, what percentage of the total number of compressor cylinders will be loaded after start up? 0 (%) 100 (%) 25 (%) 50 (%) Refrigeration & Air Conditioning
A What is the purpose of the low pressure cut-out switch as used as a primary controller for a refrigeration system or unit? start and stop the compressor as needed control the capacity of the compressor maintain a preset suction pressure to the compressor maintain a preset low-side pressure for the system Refrigeration & Air Conditioning
A A box solenoid valve used in a multi-box refrigeration system is operated by electromagnetic action by what control device? box temperature actuated thermostat discharge pressure actuated pressure switch suction pressure actuated pressure switch evaporator outlet temperature actuated thermostat Refrigeration & Air Conditioning
B How does a refrigeration solenoid valve differ from a modulating valve? Both valves operate in exactly the same manner, only the manufacturer's terminology is the differentiating factor. A liquid line solenoid valve is either completely opened or closed, whereas a modulation valve is infinitely positioned according to the strength of the applied electrical signal. Solenoid Valves are only used in low voltage refrigeration control systems, while modulation valves are used in high voltage applications. A solenoid valve can only be installed in liquid lines. Refrigeration & Air Conditioning
D A container unit's microprocessor-controlled temperature controller is set at -28.9 C, appropriate for a frozen cargo of ice cream. In this mode of operation, according to the illustrated temperature controller functional diagrams, what should be the operational status of the unit if the actual box temperature is -18.0 C? Illustration GS-RA-35 heating mode modulating cooling mode air circulation mode cooling mode Refrigeration & Air Conditioning
A Which of the following electrically operated refrigeration system valves would be most appropriate for use as a 2 position diverting hot gas bypass solenoid valve? Illustration GS-RA-19 B D C A Refrigeration & Air Conditioning
B In a multi-evaporator refrigeration system, a solenoid valve is installed in the liquid line prior to what device? the receiver each expansion valve the oil separator the condenser Refrigeration & Air Conditioning
A A liquid line solenoid valve controls refrigerant flow to the evaporator by what means? fully opening or closing sensing the temperature in the liquid line throttling the refrigerant sensing the superheat in the tail coil Refrigeration & Air Conditioning
A The thermostat controlling the operation of the solenoid valve to a refrigerated box evaporator senses what temperature? the refrigerated box temperature compressor discharge temperature evaporator coil outlet temperature evaporator coil inlet temperature Refrigeration & Air Conditioning
D In a refrigeration system featuring low-side pump down prior to the automatic shut down of the compressor, the temperature of the refrigerated space is controlled by the action of a thermostat wired to what device? suction line solenoid thermostatic expansion valve low pressure cutout switch liquid line box solenoid Refrigeration & Air Conditioning
A Which of the following statements is true? Illustration GS-RA-12 Valve "14" is the king solenoid, valve "28" is the chill box solenoid, and valve "36" is the freeze box solenoid. Valve "14" is the king solenoid, valves "28" and "36" are both freeze box solenoids. Valve "14" is the king solenoid, valve "36" is the chill box solenoid, and valve "28" is the freeze box solenoid. Valve "14" is the king solenoid, valves "28" and "36" are both chill box solenoids. Refrigeration & Air Conditioning
C If it is necessary to increase the operating head pressure of the refrigeration system using the device shown in the illustration, what should be done? Illustration GS-RA-14 "4" should be rotated to relax the enclosed bellows "4" should be rotated to compress the enclosed bellows "2" should be turned to further compress the spring "2" should be turned to relax the compression of the spring Refrigeration & Air Conditioning
C As shown in the illustrated refrigeration system piping schematic diagram with the various accessories and controls and equipped with an air-cooled condenser with high side pressure controls, what statement is true concerning the fan cycling control pressure switch? Illustration GS-RA-39 With a condenser fitted with multiple electric-motor driven fans, the number of fans in use would increase under low ambient temperature conditions. With a condenser fitted with a single fan driven by a multi-speed electric motor, the fan speed would decrease under high ambient temperature conditions. With a condenser fitted with a single fan driven by a multi-speed electric motor, the fan speed would decrease under low ambient temperature conditions. With a condenser fitted with a single fan driven by a single-speed electric motor, the fan would cycle off under high ambient temperature conditions. Refrigeration & Air Conditioning
C In a refrigeration system, the valve shown in the illustration is used for what purpose? Illustration GS-RA-14 suction pressure regulating valve thermostatic expansion valve head pressure regulating valve evaporator pressure regulating valve Refrigeration & Air Conditioning
D The set point adjustment of the device shown in the illustration is made by rotating what component? Illustration GS-RA-14 "3" "1" "4" "2" Refrigeration & Air Conditioning
B An arrow stamped on the valve body of a water regulating valve indicates which of the following? closed position direction of the flow open position direction of the plunger slide Refrigeration & Air Conditioning
C Which of the following illustrated expansion valves is designed to maintain a constant evaporator pressure rather than a constant evaporator superheat? Illustration GS-RA-24 D B C A Refrigeration & Air Conditioning
C Refrigeration system isolation valves are specially designed with a back-seat, as well as a front-seat. For what purpose are these valves designed in this way? allow for operation as a suction or discharge valve allow for removal and replacement of the valve without shutting down permit repacking the valve stem under pressure without shutting down allow for operation as a liquid or vapor valve Refrigeration & Air Conditioning
D In addition to pressure, most compound and standard pressure gauges used for refrigeration service are also provided with a scale indicating what parameter? superheated refrigerant temperature sub cooled refrigerant temperature absolute pressure saturated refrigerant temperature Refrigeration & Air Conditioning
A What is the purpose of the pressure transducer as shown in the illustration? Illustration GS-RA-17 it senses compressor suction pressure and controls the quench valve it senses compressor suction pressure and controls the suction modulation valves it senses compressor discharge pressure and controls the suction modulation valves it senses compressor discharge pressure and controls the quench valve Refrigeration & Air Conditioning
B Which lettered component, shown in the illustration, indicates the location of the receiver? Illustration GS-RA-12 B C F A Refrigeration & Air Conditioning
C In a refrigeration plant, what is one vital purpose of the receiver? condense the refrigerant cool the refrigerant gas store the refrigerant charge superheat the refrigerant liquid Refrigeration & Air Conditioning
B In addition to the indicated gauge pressure, what other information is presented on the compound gauge for the hypothetical refrigerant illustrated? Illustration GS-RA-16 the actual temperature of the refrigerant at the point of measurement the saturation temperature of the refrigerant that corresponds to the gauge pressure at the point of measurement the absolute pressure of the refrigerant at the point of measurement the metric pressure equivalent of the refrigerant at the point of measurement Refrigeration & Air Conditioning
C The receiver used in a refrigeration system performs what essential function? prevents liquid refrigerant from flooding back to the compressor allows the refrigerant to be superheated holds the entire refrigerant charge after system pump down collects air and non-condensable gases Refrigeration & Air Conditioning
B Hard drawn copper tubing is commonly used in larger refrigeration systems. What statement concerning its use is true? Hard drawn copper tubing is easily bent, so elbow fittings are rarely used in changing direction. Hard drawn copper tubing is not easily flared, bent, or swaged, so brazed fittings are commonly used. Hard drawn copper tubing is easily flared, so flare fittings are commonly used. Hard drawn copper tubing is easily swaged, so reducing fittings are rarely used in changing line size. Refrigeration & Air Conditioning
B In a large refrigeration system having more than one evaporator, a king solenoid valve should be installed in what location? before the condenser just after the receiver before the back pressure regulating valve between the condenser and receiver Refrigeration & Air Conditioning
C If the valve labeled "D" in the illustration is a suction service valve, what will the port labeled "7" be connected to? Illustration RA-0008 to the outlet of the compressor to the inlet of the compressor to the line connected to the evaporator outlet to the line connected to the evaporator inlet Refrigeration & Air Conditioning
C As shown in the illustrated LP centrifugal chiller pressure maintenance system, what is its functional purpose? Illustration GS-RA-40 prevent the entrance of air into the chiller under low heat load conditions prevent surging prevent the entrance of air into the chiller when the chiller is idle maintain a relatively low compression ratio under low heat load conditions Refrigeration & Air Conditioning
C During the initial cooling down of a box temperature in a refrigeration system, which of the devices listed is used to prevent excessive gas pressure at the compressor suction for the purpose of prevention of overloading of the compressor driver? Low pressure cutout Solenoid valve Crankcase pressure regulator High pressure cutout Refrigeration & Air Conditioning
D Which of the lettered components shown in the illustration indicates the high-pressure cut-out? Illustration GS-RA-12 Y Z W X Refrigeration & Air Conditioning
C In a refrigeration system that is not protected by a water failure switch, if the cooling water to the condenser fails, what will be the result for protective purposes? the king valve will open the expansion valve will close due to high superheat the compressor will shut down by the action of the high pressure cutout switch the box temperature solenoid valve will close initiating a pump down Refrigeration & Air Conditioning
A When the relief valve opens on a refrigeration compressor discharge line, it discharges high pressure refrigerant vapor to what location? suction side of the compressor inlet side of the evaporator refrigerant inlet of the condenser liquid strainer Refrigeration & Air Conditioning
D The rupture disc on a low pressure centrifugal refrigeration unit is used as an over pressure protection device and is set to relieve at 15 psig and is most likely to lift when the compressor is idle? Where is the rupture disc located? on top of the condenser shell at the discharge of the compressor at the top of the upper chamber of the economizer on top of chiller evaporator shell Refrigeration & Air Conditioning
A In a refrigeration system, what component is installed directly downstream of the thermal expansion valve? evaporator coil receiver compressor box solenoid valve Refrigeration & Air Conditioning
B Refrigeration systems using forced air circulation evaporators have a tendency to cause rapid dehydration of produce in chill boxes. Which of the following will minimize this dehydration? the air is circulated slowly over a large evaporator with a maximum temperature differential the air is circulated slowly over a large evaporator with a minimum temperature differential the air is circulated rapidly over a small evaporator with a maximum temperature differential the air is circulated rapidly over a small evaporator with a minimum temperature differential Refrigeration & Air Conditioning
B In a dry-type direct expansion refrigeration evaporator, what is true concerning the evaporator coils? the coils are surrounded on the outside by refrigerant the coils are surrounded on the outside by air the coils are coated on the inside with insulation the coils are covered on the outside with insulation Refrigeration & Air Conditioning
B Seawater or low temperature central fresh water is typically provided to a ship's stores refrigeration plant for what purpose? prevent motor overheating condense the refrigerant gas prevent refrigerant superheating cool the expansion valve Refrigeration & Air Conditioning
B Heat is removed from the refrigerant circulating through the refrigeration system, shown in the illustration, by which component? Illustration GS-RA-12 K B J A Refrigeration & Air Conditioning
B If a condenser coil of an air-cooled container refrigeration system becomes dirty and requires cleaning, what would be an acceptable method of cleaning? Binks' gun with weak acid solvent high pressure water wash copper wire rotary brush All of the above. Refrigeration & Air Conditioning
C When checking zinc plates, or pencil Zincs in the refrigerating system condenser, what should you do? renew the plates at each inspection file the plates to change the negative value replace the Zincs if deteriorated by 50% paint and insulate the plates to prevent corrosion Refrigeration & Air Conditioning
C What is true concerning the accumulation of air and other non-condensable gases in a refrigeration system? cause a loss of the liquid seal cause foaming of the oil in the crankcase collect in the condenser create a vapor lock in the liquid receiver Refrigeration & Air Conditioning
D Zinc plates commonly found in refrigeration systems and used as sacrificial anodes are located where? cooling water suction strainer refrigerant side of the condenser evaporator coils saltwater side of the condenser Refrigeration & Air Conditioning
D Through which of the components shown in the illustration is flash gas formation a normal occurrence? Illustration GS-RA-25 evaporator coil condenser coil receiver tank thermostatic expansion valve Refrigeration & Air Conditioning
C In a refrigeration system, the pressure within the power element of a thermostatic expansion valve depends directly upon what factor? compressor suction pressure temperature in the box temperature of the evaporator coil outlet heat transferred from the saturated liquid in the evaporator Refrigeration & Air Conditioning
B In the multi-evaporator refrigeration system shown in the illustration, what is the proper name for the valve labeled "29"? Illustration GS-RA-12 chill box solenoid valve chill box thermostatic expansion valve freeze box thermostatic expansion valve chill box evaporator pressure regulating valve Refrigeration & Air Conditioning
A Rather than design an infinite variety of thermostatic expansion valve sizes to accommodate different capacities for heat removal, some manufacturers use a few standard valve body sizes in conjunction with what other feature? internal needle valve orifices of various sizes to accommodate different heat removal capacities an externally adjustable superheat to accommodate different heat removal capacities internal equalizers to accommodate different heat removal capacities a flexible diaphragm to accommodate different heat removal capacities Refrigeration & Air Conditioning
A Constant superheat is maintained at the evaporator coil outlet of a refrigeration system or unit by the action of what device? thermal expansion valve king valve low pressure cutout switch solenoid valve Refrigeration & Air Conditioning
C Besides the evaporator pressure, the thermal expansion valve reacts directly to changes in what parameter? pressure drop across the evaporator coils liquid refrigerant pressure at the solenoid valve temperature of the evaporator coil outlet temperature of the space being cooled Refrigeration & Air Conditioning
B Which of the following illustrated expansion valves is designed to maintain a constant evaporator pressure rather than a constant evaporator superheat? Illustration GS-RA-24 D C A B Refrigeration & Air Conditioning
B Which of the following illustrated thermal expansion valves would be appropriate to use on an evaporator coil with a 2 psi pressure drop, where externally adjustable superheat and a replaceable power element are both desired? Illustration GS-RA-06 C B A D Refrigeration & Air Conditioning
D What is one function of the thermal expansion valve used in a refrigeration system? act as a pilot controlling the box solenoid valve turn the compressor off and on regulate the water flow to the water-cooled condenser regulate the amount of refrigerant flow to the evaporator coil Refrigeration & Air Conditioning
A When a refrigeration compressor is in the 'off' cycle, the thermal expansion valve will react in what way? it will continue to function as a result of the net balance of forces acting on the diaphragm it will always remain in the same position just prior to the cycling off of the compressor it will always completely close regardless of whether or not the system employs a pump down cycle it will always open wide regardless of whether or not the system employs a pump down cycle Refrigeration & Air Conditioning
A Of the various possible methods shown in the illustration, which is the correct method of attaching a TXV feeler bulb to a small large line (7/8" and larger) with a horizontal run? Illustration GS-RA-50 C D A B Refrigeration & Air Conditioning
C When a thermostatic expansion valve is installed in a refrigerated container unit, the sensing bulb almost always requires insulation. Why is this so? the insulation prevents the bulb from vibrating loose the insulation prevents oil entrained in the suction gas from influencing the bulb temperature the insulation prevents air stream temperatures from influencing the bulb temperature the insulation protects the clamp and screws from corrosion Refrigeration & Air Conditioning
C A thermostatic expansion valve is properly controlling evaporator superheat. Adjusting this valve to lower the evaporator superheat setting will result in which of the following? the evaporator pressure will decrease the expansion valve will further close the evaporator feed will increase the expansion valve diaphragm will rupture Refrigeration & Air Conditioning
D When replacing a thermostatic expansion valve power element, what is true concerning the thermal bulb? apply a heavy coating of grease to function as a heat sink apply a light film of oil to increase heat transfer carefully coat the device with silicone sealant to reduce the effects of convective cooling with steel wool or an abrasive cloth remove oxidation on the bulb and suction line Refrigeration & Air Conditioning
D Expansion valve maintenance should include which of the following procedures? Cleaning of in-line strainers as necessary. Ensuring that the thermal bulb is in good contact with the suction line and insulated. Checking that the thermal bulb is in the proper location. All of the above. Refrigeration & Air Conditioning
D Which statement about calibrating a newly installed thermostatic expansion valve is correct? This procedure is done at the factory with tools not available to a mariner. The procedure requires a refrigeration wrench and a digital thermometer to measure box temperature. No special tools are required as long as the solid state circuit control panels are functioning properly. An accurate thermometer and suction pressure gage are essential to this process. Refrigeration & Air Conditioning
C Which of the installation steps listed is necessary for the proper operation of the thermostatic expansion valve? Attach the thermal bulb to the suction line using plastic ties. Heat shrink insulating material around the device once the bulb has been properly secured. Clean off oxidation from the surface of the suction line and sensing bulb with fine abrasive cloth or steel wool. Remove excess lengths of the sensing bulb capillary tube from the device to increase sensitivity. Refrigeration & Air Conditioning
B Which of the listed statements describes the method used to determine the amount of superheat present in the suction gas leaving the evaporator coil? Illustration GS-RA-16 Note the low side pressure, determine the corresponding saturation temperature, and add it to the temperature measured with a thermometer at the thermostatic expansion valve sensing bulb. Note the low side pressure, determine the corresponding saturation temperature, and subtract it from the temperature measured with a thermometer at the thermostatic expansion valve sensing bulb. Note the low side pressure, determine the corresponding saturation temperature, and subtract it from the temperature measured with a thermometer at the compressor suction inlet. Subtract the temperature measured at the thermostatic expansion valve sensing bulb from the saturation temperature corresponding to the low side pressure. Refrigeration & Air Conditioning
B What maintenance may be carried out on a thermostatic expansion valve? The rate action may be increased. The inlet screen may be cleaned. The thermal bulb may be recharged. The proportional action may be varied. Refrigeration & Air Conditioning
C Moisture entering a typical refrigeration system will most likely produce what effect? cause sweating and frost on the evaporator coils boil in the condenser freeze in the expansion valve be removed by the liquid line strainers Refrigeration & Air Conditioning
D Which of the following conditions will occur if the power element of the thermostatic expansion valve shown in the illustration loses its charge? Illustration GS-RA-07 The valve will fail open and the cooling capacity will be increased. The valve will begin to close, but the external equalizing line will assist in keeping the valve unseated. The valve will fail open as designed to provide continuous cooling. The valve will fail closed, providing no cooling capacity. Refrigeration & Air Conditioning
C If the superheat setting of a thermostatic expansion valve is set too low, what would be the result, assuming that the system has a single evaporator? the receiver level will be abnormally high due to a reduced amount of refrigerant returning back to the compressor the box temperature will be pulled way down below the normal temperature range the suction line will be abnormally cold and liquid may flood back to the compressor the suction line will be abnormally warm due to a reduced amount of refrigerant returning back to the compressor Refrigeration & Air Conditioning
A If the superheat value of the thermostatic expansion valve is adjusted too high, what would be the result? the suction line of the compressor will be abnormally warm the heat removal capacity of the evaporator will increase the suction line of the compressor will be abnormally cold the evaporator will be overfed with liquid refrigerant Refrigeration & Air Conditioning
D A small obstruction at the thermostatic expansion valve inlet will result in which of the following conditions? Higher than normal discharge pressure. Expansion valves are designed to pass small foreign particles so no adverse condition will occur. Ice is the sole cause of this and will soon melt due to superheat; no adverse condition will occur. Lower than normal suction pressure. Refrigeration & Air Conditioning
A An obstructed expansion valve may be indicated by an incompletely cooled evaporator and what other symptom? frosting at the evaporator inlet a higher than normal discharge pressure a decrease in the amount of frosting across the drier frosting at the suction side of the compressor Refrigeration & Air Conditioning
D If the needle and seat assembly is excessively eroded, the valve cage assembly can be replaced. In replacing the original valve cage assembly rated at 1/2 tons, what would be the result if the replacement valve cage was oversized at 5 tons? Illustration GS-RA-07 The evaporator would be overfed producing consistently insufficient superheat. The expansion valve would function normally, with the presentation of no problems. The evaporator would be starved producing consistently excessive superheat. The expansion valve would hunt excessively, alternately starving and overfeeding the evaporator coil. Refrigeration & Air Conditioning
C Vapor bubbles present in the liquid upon arrival to the thermal expansion valve in a refrigeration system may cause erosion of the expansion valve's needle and seat. This, in turn, could cause what condition? TXV freezing shut TXV freezing open TXV hunting TXV overheating Refrigeration & Air Conditioning
C Some 'hot gas' defrost systems reheat the refrigerant just prior to its returning to the compressor for what purpose? to prevent chill shocking the compressor suction valves to improve the efficiency of the expansion valve to prevent the damaging effects of liquid slugging to increase the circulation of liquid refrigerant Refrigeration & Air Conditioning
A What is true concerning frost build-up on the evaporator coils of a multi-box direct expansion refrigeration system? the frost can be removed by passing hot gas through the coils or energizing defrost heaters with the evaporator fan shut down the frost can be removed by passing hot gas through the coils or energizing defrost heaters with the evaporator fan still running the frost will increase the refrigeration effect the frost can be quickly removed by simply shutting down the compressor Refrigeration & Air Conditioning
B Concerning frost appearing on one set of evaporator coils of a multi-box, direct expansion type refrigeration system, what is true? the frost will increase the value of superheat to the fluid leaving the coils the frost can be removed by passing hot vapors through the coils the frost can be quickly removed by simply shutting off fluid flow to the coils the frost will assist in increasing the refrigeration effect Refrigeration & Air Conditioning
B A box solenoid valve used in a refrigeration system should be installed in what manner? upright, controlled by a thermostat sensing evaporator superheat, and upstream of the thermal expansion valve upright, controlled by a thermostat sensing the temperature of the box, and upstream of the thermal expansion valve with the axis of the solenoid horizontal, controlled by a thermostat sensing the temperature of the box, and upstream of the thermal expansion valve upright, controlled by a thermostat sensing the temperature of the box, and downstream of the thermal expansion valve Refrigeration & Air Conditioning
D You are checking the supply chilled water temperature thermistor probe on a high-pressure hermetic centrifugal chiller. Using the illustrated chart, what statement is true if the supply water temperature is verified 45 F with a digital thermometer __________. Illustration GS-RA-48 When checked with control power off and the thermistor probe isolated, the thermistor probe voltage drop should be 3.805 volts. When checked with control power on and the thermistor probe isolated, the thermistor probe voltage drop should be 3.805 volts. When checked with control power on and the thermistor probe connected into the circuit, the thermistor probe voltage drop should be 11.416 volts. When checked with control power on and the thermistor probe connected into the circuit, the thermistor probe voltage drop should be 3.805 volts. Refrigeration & Air Conditioning
D Which of the precautions listed should be taken before opening any part of a refrigeration system for the purpose of accomplishing non-major repairs? Bring the part of the system to be opened to a pressure corresponding to the ambient temperature. Use the hot gas defrost line to remove any frost on the evaporator coils. Set the high pressure cutout on manual to prevent automatic starting. Bring the part of the system to be opened to 0 psig. Refrigeration & Air Conditioning
D The pressure in the part of a high pressure refrigeration system about to be opened for a non-major repair should be brought to what value? 11 to 12 psig 4 to 7 psig 1 to 2 psig 0 psig Refrigeration & Air Conditioning
D Overfilling a refrigerant container is extremely dangerous because of the high pressures generated. The generation of pressure is the result of what? discharge pressure from the recovery cylinder vapor pressure of the refrigerant at saturation temperature discharge pressure of the recovery compressor hydrostatic pressure of the expanding liquid Refrigeration & Air Conditioning
B The FIRST thing to do to ensure that a refrigeration unit will not start while undergoing repairs is to do what? make a log book entry secure and tag the electrical circuit inform all persons in the area not to start the unit place a crow bar in the flywheel of the unit Refrigeration & Air Conditioning
A What is the maximum volume to which refillable refrigeration cylinders should be filled? 80% full 70% full 90% full 60% full Refrigeration & Air Conditioning
D When a refrigeration compressor has developed a high head pressure as a result of a refrigerant overcharge, what should be done to compensate for or to correct this situation? raise the high pressure cut-out opening pressure increase the amount of cooling water to the condenser decrease the amount of cooling water to the condenser remove some refrigerant from the system Refrigeration & Air Conditioning
B A high-pressure centrifugal chiller currently charged with R-134a is being evaluated for the need for leak testing. Using the leak-test procedures decision tree illustrated and the R-134a pressure-temperature chart illustrated, with the machine idle and the pressures equalized at 10 psig with an ambient temperature of 60 F, what statement is true? Illustration GS-RA-47 The machine has a suspected leak, therefore nitrogen should be added to bring the pressure to 70 psig prior to checking for leaks. The machine has a suspected leak, therefore the refrigerant pressure should be raised to 35 psig by adding refrigerant prior to checking for leaks. The machine definitely does not have a leak, therefore no attempt at leak detection is necessary. The machine may or may not have a leak, therefore the machine should be checked for leaks without any adjustments in pressure. Refrigeration & Air Conditioning
B When using nitrogen to pressure leak test a system, the nitrogen cylinder should always be equipped with what device or feature? temperature indicator pressure regulator blue top level indicator Refrigeration & Air Conditioning
C Which of the following statements is correct concerning the testing of an R-22 refrigeration system for leaks in an enclosed compartment with a halide torch? The flame of a halide torch will turn blue in the presence of R-22. Halide torches are not suitable for detecting R-22 leaks. Halide torches are useful in locating very small R-22 leaks. To gain sensitivity, the largest possible flame should be used with the halide torch. Refrigeration & Air Conditioning
A In a refrigeration system, from what location would air and non-condensable gases be removed? the top of the condenser purge connection expansion valve equalizer connection the bottom of the receiver drain connection compressor oil fill connection Refrigeration & Air Conditioning
C Loss of refrigerant during the process of purging of air and non-condensable gases can be kept to a minimum by what action? purging through a dehydrator purging through the top of the receiver rather than the top of the condenser cracking the purge valve briefly and allowing the refrigerant to re-settle between purges purging through the discharge service valve rather than the top of the condenser Refrigeration & Air Conditioning
D In a low-pressure centrifugal chiller, what is meant by the term 'high efficiency purge unit? Those purge units which need the least amount of on-going Maintenance. Those purge units which draw very little electrical power. Those purge units which discharge the highest percentage of refrigerant with the air being removed. Those purge units which discharge very little refrigerant with the air being removed. Refrigeration & Air Conditioning
B During normal operation, traditionally, how has most of the refrigerant released to the atmosphere from low pressure systems? through water-side system leaks through the purge unit vent through the compressor shaft seal through a leaking rupture disk Refrigeration & Air Conditioning
D If you find a refrigerant leak while using a halide torch, what will happen to the flame as the exploring tube approaches the leak? it will change from green to blue it will change from blue to orange it will stay blue it will change from blue to green Refrigeration & Air Conditioning
D After the refrigerant has been recovered, leaks repaired if necessary, the system ideally should undergo a dehydration evacuation prior to recharging with refrigerant. As shown in the illustration, besides the vacuum pump suction manifold isolation valve being opened, what would be the proper valve positions to accomplish and prove the evacuation? Illustration GS-RA-51 Valves 1, 2, and 3 should be back-seated and both gauge manifold hand valves should be open. Valves 1, 2, and 3 should be front-seated and both gauge manifold hand valves should be closed. Valves 1, 2, and 3 should be in the mid-position and the low-side gauge manifold hand valve should be open, and the high-side gauge manifold hand valve should be closed. Valves 1, 2, and 3 should be in the mid-position and the low-side gauge manifold hand valve should be closed, and the high-side gauge manifold hand valve should be open. Refrigeration & Air Conditioning
B Concerning the operation of refrigeration systems, frosting or sweating of a liquid line is usually indicative of what condition? high relative humidity surrounding the liquid line a liquid line restriction the refrigerant contaminated with moisture proper cooling taking place Refrigeration & Air Conditioning
D An air-cooled refrigerated container unit using R-134a as a refrigerant has a box temperature set point of -15 F, but it is currently operating with a stable return air temperature of 0 F. The fresh air makeup vent is closed, the unit is operating at 460 VAC/60 Hz, and the unit is in full capacity cool (modulating valve 100% open). Using the illustrated troubleshooting guide, what would be the normal range of expected discharge pressures if the ambient air temperature is 90 F? GS-RA-52 190-230 psig 200-220 psig 160-180 psig 150-190 psig Refrigeration & Air Conditioning
D High suction pressure accompanied by low suction temperature to a refrigeration system compressor is caused by which of the following? the expansion valve is insufficiently opened the king valve is insufficiently open a clogged liquid-line strainer the expansion valve being open too wide Refrigeration & Air Conditioning
C Which of the conditions listed could cause excessively low refrigerant pressure at the compressor suction of a TXV controlled refrigeration system? The high pressure cutout switch is inoperative. Insufficient flow of condenser cooling water. The system is low on refrigerant. The box solenoid valve 'stuck' in the open position. Refrigeration & Air Conditioning
A Low compressor head pressure in a refrigeration system can be caused by which of the following? excessive condenser cooling water flow insufficient condenser cooling water flow excessive refrigerant in the system air in the refrigeration system Refrigeration & Air Conditioning
D In an operating, water-cooled, multi-box refrigeration system, both low discharge and high suction pressures are being simultaneously experienced. The probable cause for this condition is which of the following? improper superheat adjustment on the low side fouled shell-and-tube condenser overcharge of refrigerant in the system discharge relief valve leaking back to the suction side Refrigeration & Air Conditioning
C If the running suction pressure at the refrigeration compressor of a TXV controlled air-cooled refrigeration system is below normal, which of the following can be a cause? a dirty condenser overfeeding by the expansion valve a restricted liquid-line strainer refrigerant overcharge Refrigeration & Air Conditioning
B If increasing the cooling water flow to a refrigeration condenser fails to lower the condenser pressure, the probable cause may be due to what condition? a low level of Freon in the receiver excessive amount of non-condensable gases trapped in the condenser an evaporator coil in need of defrosting partially blocked thermal expansion valve Refrigeration & Air Conditioning
B A refrigeration unit will tend to short cycle when operating under what conditions? during starting conditions lack of refrigerant during hot gas defrost under heavy loads Refrigeration & Air Conditioning
B If the refrigeration compressor crankcase is sweating or frosting and is operating with an unusual noise, what is most likely the cause? the compressor running continuously liquid refrigerant returning to the compressor a shortage of refrigerant the compressor short cycling on the high pressure cutout Refrigeration & Air Conditioning
D If a refrigeration system, equipped with a reciprocating compressor, has a liquid-line solenoid valve that is leaking during the 'off' cycle, what would this cause? refrigerant slugs in the receiver high superheat in the outlet coil low suction pressure noisy compressor operation upon starting Refrigeration & Air Conditioning
C If a refrigeration compressor had developed a slightly high suction pressure accompanied with an abnormally low suction temperature, the problem could be a result of which of the following? a clogged sub cooler a leaking king valve liquid refrigerant flooding back from the cooling coil a minor accumulation of air or non-condensable gases in the system Refrigeration & Air Conditioning
B An excessive charge of refrigerant in a thermostatically controlled, air-cooled, refrigeration system using a TXV as an expansion device can cause which of the following? the compressor to run continuously higher than normal discharge pressure lower than normal box temperature oil foaming in the compressor Refrigeration & Air Conditioning
C If a refrigeration compressor using a thermostat as a primary controller is running continuously without significantly lowering the temperature in the refrigerated space, which of the following is most likely the trouble? a shortage of compressor oil warm food in the refrigerator a shortage of refrigerant excessive condenser cooling water Refrigeration & Air Conditioning
B During tests to discover why a refrigeration compressor is running continuously, it is determined that the refrigerated space temperature is slightly above normal without ever reaching the desired minimum temperature. Suction and discharge pressures are normal for the corresponding box temperature. In this situation, what should you suspect? air in the system leaking door gaskets a shortage of refrigerant high cooling water temperature Refrigeration & Air Conditioning
A If a refrigeration system were short of refrigerant, besides an elevated box temperature, what would be an observable symptom? continuous running of the compressor short cycling of the compressor on the water failure switch high suction pressure high discharge pressure Refrigeration & Air Conditioning
A If a refrigeration compressor were short cycling on the low pressure cutout switch, what is the most probable cause? the expansion valve strainers were fouled the suction valves were leaking slightly the high pressure switch was improperly adjusted the system was overcharged with refrigerant Refrigeration & Air Conditioning
A When a refrigeration compressor motor fails to start, the FIRST thing that should be checked for is what? blown fuse or tripped circuit breaker in the motor circuit faulty suction pressure regulator loose expansion valve control bulb low differential setting on the H.P. cutout Refrigeration & Air Conditioning
C If the evaporator coil horizontal return line of a container refrigeration system is less than 0.875" (2.21 cm) in diameter (considered small), the thermostatic expansion valve sensing bulb should be attached where on the return line? as close as possible to the expansion valve directly below the point of maximum heat transfer on the upper surface of the line on the bottom of the line to enable the bulb to absorb the maximum amount of heat Refrigeration & Air Conditioning
B For safe storage, the maximum allowable temperature to which refrigerant bottles should be exposed is what temperature? 150F 125F 175F 100F Refrigeration & Air Conditioning
C Overfilling a refrigerant container is extremely dangerous because of the high pressures generated. The generation of pressure is the result of what? discharge pressure from the recovery cylinder vapor pressure of the refrigerant at saturation temperature hydrostatic pressure of the expanding liquid discharge pressure of the recovery compressor Refrigeration & Air Conditioning
C Personnel servicing refrigeration systems and subject to the exposure to commonly used refrigerants should wear what type of personal protective equipment? an all purpose gas mask rubber soled shoes goggles and gloves a respirator Refrigeration & Air Conditioning
D In the presence of an open flame or hot surfaces, chlorinated fluorocarbon refrigerants decompose and form what chemical substance? petroleum crystals water vapor carbon monoxide phosgene gas Refrigeration & Air Conditioning
A Why can CFC or HCFC refrigerants leaking into a confined space or in limited surroundings cause suffocation? Refrigerants are heavier than air and displace oxygen. Refrigerants contain an acidic substance. Refrigerants obnoxious odor prevents breathing. Refrigerants lighter than air will rise. Refrigeration & Air Conditioning
A Traditionally, which of the listed refrigerants has been more suitable than the others for use in a centrifugal refrigeration compressor? R-11 Carbon dioxide R-12 Ammonia Refrigeration & Air Conditioning
B Which of the fluids listed is suitable for use as a secondary refrigerant? Cuprous chloride Brine Methyl alcohol Carbon dioxide Refrigeration & Air Conditioning
B What is the purpose of running a refrigeration compressor in short intermittent spurts or throttling the suction isolation valve when starting the system after a prolonged shutdown? let the refrigerated compartment cool gradually prevent liquid slugging or overloading the compressor allow refrigerant vapor cycling time determine actual compressor oil level Refrigeration & Air Conditioning
A When starting a reciprocating refrigeration compressor that has been shut down for a period of time, you should manually throttle which valve? suction valve sea water valve king valve expansion valve Refrigeration & Air Conditioning
C When opening or closing compressor service and line isolation valves on a typical refrigeration system that is fitted with packed valves, what must you do? you should replace the gasket each time the valve position is changed you should never loosen or tighten the packing gland you must first remove the stem seal cap you should turn valves slowly to avoid thermal stresses due to low temperatures Refrigeration & Air Conditioning
C Alkylbenzene ISO 32 cSt synthetic refrigerant oil is miscible and suitable to use with which of the following refrigerants? R-134a R-143a R-22 R-32 Refrigeration & Air Conditioning
C Coast Guard Regulations (46 CFR Part 58) require a method for the relieving pressure of an over pressurized refrigeration system. Which of the following statements complies with these Regulations? The relief valve from the receiver must relieve to the condenser first. The relief valve settings shall be 1 1/4 times the maximum allowable working pressure. A rupture disk may be fitted in series with the relief valve. The rupture disk shall burst at a pressure not higher than 10% above the relief valve setting. Refrigeration & Air Conditioning
A In an air conditioning system, what is the name of the chamber where the duct-work originates? plenum chamber vapor chamber exhaust chamber intake chamber Refrigeration & Air Conditioning
B Coast Guard Regulations (46 CFR Part 113) require refrigerated spaces that can be locked from the outside and that cannot be opened from the inside to have an audible alarm. Where is the audible alarm required to be? the galley a manned location the wheelhouse the chief steward's berthing quarters Refrigeration & Air Conditioning
C In a two stage centrifugal air conditioning system, the liquid refrigerant passes through the condenser directly to what component? chiller evaporator economizer expansion valve Refrigeration & Air Conditioning
A A reheater in an air conditioning system performs what function? restores the conditioned air temperature to a comfortable level controls the inlet air volume maintains the relative humidity at 15% controls the inlet air temperature Refrigeration & Air Conditioning
C With regards to shipboard refrigeration systems, after July 1, 1992, what action became illegal? working on a refrigeration system without permission of the Officer in Charge Marine
Inspection
producing a class I refrigerant intentionally venting class I or II refrigerants to the atmosphere mixing R-12 and R-22 Refrigeration & Air Conditioning
A Refillable tanks used to ship CFC and HCFC refrigerants or used to recover these refrigerants must meet the standards of what entity? the United States Department of Transportation the Environmental Protection Agency the United States Coast Guard the Underwriters Laboratories Refrigeration & Air Conditioning
B What is one benefit of Maintenance of proper air circulation in an air conditioned cargo space? more temperature differential reduced slime and mold increased moisture content increased density of the air Refrigeration & Air Conditioning
D According to 46 CFR, Part 58, for protection purposes, what is required of all refrigeration systems? refrigerant receiver high pressure cut-out low pressure cut-out pressure relief device Refrigeration & Air Conditioning
C What is the wet bulb temperature of air if the dry bulb temperature of the air is 90 degrees and the relative humidity is 65%? Illustration GS-RA-22 62 degrees F 63 degrees F 80 degrees F 77 degrees F Refrigeration & Air Conditioning
D In general, the thermal bulb for a thermal expansion valve used in a reciprocating air conditioning system is usually charged with what substance? mercuric sulfate bees wax distilled water the same refrigerant as the system Refrigeration & Air Conditioning
D To prevent the unnecessary loading of an air conditioning system while maintaining the designed dry bulb temperature and relative humidity in an air conditioning system, what should be done? reduce the air reheating system load lower the compressor head pressure operate the purge recovery unit continuously admit only enough fresh outside air to provide proper ventilation Refrigeration & Air Conditioning
C What would be an example of a small appliance as defined in the EPA Clean Air Act rules? a 25 ton air conditioning system set up as a split plant with the condensing unit on deck a 200 ton low pressure centrifugal chiller for cargo hold air conditioning a hermetically sealed water cooler with a 2 lb. refrigerant charge a self-contained walk-in freezer with a 60 lbs. refrigerant charge Refrigeration & Air Conditioning
A Which of the following is true concerning the class "D" air conditioning system shown in the following illustration? Illustration GS-RA-42 The duct thermostat determines the amount of water flow circulating through the cooling coil. System cooling is the direct result of the Freon circuit of a direct type air conditioning unit. The heat load will increase by increasing the amount of recirculated air. The room thermostat controls the wet bulb temperature of the air conditioned space. Refrigeration & Air Conditioning
B Concerning the arrangement of equipment and associated hoses shown in the illustration, which statement is true? Illustration GS-RA-59 When recovering refrigerant from the centrifugal chiller using this method, the entire charge may be removed in one procedure. When recovering refrigerant from the centrifugal chiller using this method, it is possible to achieve the recovery levels required by law without any further recovery. When recovering refrigerant from the centrifugal chiller using this method, the containment tank should be vented back to the chiller evaporator shell. When recovering refrigerant from the centrifugal chiller using this method, the refrigerant is being recovered as a liquid. Refrigeration & Air Conditioning
B Which best defines a "Type I" small refrigeration appliance according to the EPA Regulations Section 608? refrigerators, freezers, room air conditioners and central air conditioners systems manufactured and hermetically sealed having a capacity of five pounds (2.27 kg) or less of refrigerant any appliance charged with less than two pounds (0.91 kg) of refrigerant any appliance charged with less than ten pounds (4.54 kg) of refrigerant Refrigeration & Air Conditioning
C Which of the following methods is normally used to control the circulated air temperature of an air conditioning system using chilled water circulation? A regulating valve changes the inlet temperature of the water in the cooling coils. A fan speed controller regulates the amount of air flowing across the coils. A regulating valve controls the quantity of chilled water flowing in the cooling coils. Control dampers varying the number of passes the air makes across the cooling coils. Refrigeration & Air Conditioning
A For the proper control of the air temperature in an air conditioning system using chilled water circulation, which of the listed conditions should remain constant regardless of load changes? Chilled water system supply temperature. Chilled water system return temperature. Compressor discharge temperature. Compressor suction pressure. Refrigeration & Air Conditioning
D If you find the pressure of a refrigeration system containing a Class I or Class II refrigerant to be opened for the accomplishment of repairs is 0 psig, what must be done? only recover the vapor refrigerant only recover the liquid refrigerant in the system recover liquid and vapor refrigerant and have it reclaimed do not attempt to recover the refrigerant and repair the leak before pulling a vacuum on the system Refrigeration & Air Conditioning
B EPA Clean Air Act rules permit refrigerant to be released to the atmosphere under which of the following conditions? when testing a system for leaks using R-12 and nitrogen when release is considered 'de minimis' when adding oil to a compressor during replacement of a compressor Refrigeration & Air Conditioning
B Which of the processes listed would be the most satisfactory method to use to lower the humidity of the air being circulated by an air conditioning system? Heating the air and then cooling it to a point below dew point. Cooling the air to a point below dew point, then reheating it. Cooling the air to a temperature just above dew point. Heating the air to a point at which moisture will boil off, then recooling it. Refrigeration & Air Conditioning
A A room humidistat initiates the lowering of the humidity of the conditioned supply air to a space, while the actual process is accomplished by what means? lowering the cooling coil temperature and raising the reheater temperature raising both the cooling coil temperature and the reheater temperature lowering both the cooling coil temperature and the reheater temperature raising the cooling coil temperature and lowering the reheater temperature Refrigeration & Air Conditioning
C All shipboard personnel responsible for the maintenance and repair of air conditioning systems using refrigerants covered under the EPA Clean Air Act venting prohibition, must be certified through an approved Environmental Protection Agency (EPA) program to do which of the following? before performing any maintenance or repair regardless of the actual procedure before they can set the operating controls of the system before performing maintenance, service or repair that could reasonably be expected to release Class 1 or Class 2 refrigerants into the atmosphere before they can pump down the system in preparation for shifting over to the standby
condensing unit
Refrigeration & Air Conditioning
B In an air conditioning system, moisture is removed from the air by what means? separators cooling coils ducted traps filters Refrigeration & Air Conditioning
D When recovering R-12 from a small appliance with a working compressor, using a recovery device manufactured after November 15, 1993, what percentage of the remaining charge must be removed from the system? 99 (%) 80 (%) 75 (%) 90 (%) Refrigeration & Air Conditioning
C Persons recovering refrigerant from small appliances must be certified as what type of technician under the EPA Clean Air Act rules? Type II technician Type III technician Type I or Universal technician All of the above. Refrigeration & Air Conditioning
C The introduction of outside air to the air conditioning system is 90F with a relative humidity of 60%. The air has been conditioned to 70F with a relative humidity of 80%. Using the psychrometric chart, shown in the illustration, determine the quantity of moisture removed from one pound of the conditioned air __________. Illustration GS-RA-22 50 grains 20 grains 40 grains 30 grains Refrigeration & Air Conditioning
A According to the EPA Clean Air Act rules, what is true concerning refrigerant leaks in a small hermetically sealed shipboard water cooler with a 20 ounce charge weight? Legally, the leaks are not required to be repaired, but morally it is advisable to repair the leaks. The leaks must be repaired if the annual leak rate exceeds 15% of the total charge The leaks must be repaired within 30 days. The leaks must be repaired if the annual leak rate exceeds 35% of the total charge. Refrigeration & Air Conditioning
D If outside air at 80 degrees F and 70 percent relative humidity is conditioned, what will be the resulting dew point temperature of the air just before it comes into contact with the cooling coil? Illustration GS-RA-22 67 degrees F 73 degrees F 64 degrees F 70 degrees F Refrigeration & Air Conditioning
C Which of the following is true concerning the class "A" air conditioning system shown in the illustration as used to condition the air of large public spaces? Illustration GS-RA-09 The preheater steam flow is controlled by the space thermostat. It is not possible for both the cooling coil and the steam heated reheater to be used
simultaneously.
The dry bulb room temperature is controlled by a steam heated reheater and its associated pneumatic control valve. Illustration GS-RA-09 The reheater is not used when in the cooling mode. Refrigeration & Air Conditioning
A Within the territorial limits of the United States, violations of the Clean Air Act of 1990, that includes the intentional release of R-11, R-12, R-22 and other related class I or class II substances may result in fines for each violation per day of what amount? 25000 10000 50000 5000 Refrigeration & Air Conditioning
B To add small amounts of refrigerant to the low side of an air conditioning system, the refrigerant should be introduced through a particular valve and in a particular state. What valve and state combination is correct? discharge service valve as a vapor suction service valve as a vapor discharge service valve as a liquid suction service valve as a liquid Refrigeration & Air Conditioning
B To add refrigerant to the high side of an air conditioning system, you should close the king valve and introduce the refrigerant through what valve in what state? discharge service valve as a vapor charging valve as a liquid suction service valve as a liquid condenser purge valve as a vapor Refrigeration & Air Conditioning
C When pumping down an air conditioning system to test the low-pressure cut-out switch, assuming that the compressor is running, what should be done to initiate the test? stop the compressor secure the condenser close the "king" valve stop the circulating pump Refrigeration & Air Conditioning
A When recovering the remaining R-134a refrigerant from the centrifugal chiller shown in the illustration as a vapor using the recovery unit's compressor, in addition to opening valves "1a", "1b", and the compressor suction and discharge isolation valves, which of the following would be the correct valve lineup? Illustration GS-RA-28 valves "3", "4", and "6" open; valves "2", "5", "7", "8", and "10" closed valves "2", "5", "7", "8", and "10" open; valves "3", "4", and "6" closed valves "3", "5", and "6" open; valves "2", "4", "7", "8", and "10" closed valves "3", "4", "7", "6" and "10" open; valves "2", "5", and "8" closed Refrigeration & Air Conditioning
D The compressor used in a water-cooled air conditioning system is short cycling. A service check determines that the suction pressure remains above the normal cut-in point during cycling and that the discharge pressure rapidly builds up to the cut-out point while running and gradually falls to the cut-in point during the off cycle. What is likely the cause? front seated liquid line service valve back seated discharge service valve loosely fitted compressor drive belt reduction in condenser water flow (scaled condenser) Refrigeration & Air Conditioning
D Using the illustrated chart giving the boiling point of moisture at various depths of vacuum, with an ambient temperature of 72 F, what depth of vacuum would be associated with the BEST chance of achieving a dehydration evacuation with a deep vacuum pump? Illustration GS-RA-56 29.20" Hg or 20,320 microns of Hg absolute 28.75" Hg gauge or 31,750 microns of Hg absolute 29" Hg gauge or 25,400 microns of Hg absolute 29.99" Hg or 254 microns of Hg absolute Refrigeration & Air Conditioning
B Concerning the arrangement of equipment and associated hoses shown in the illustration, which statement is true? Illustration GS-RA-58 When recovering refrigerant from the centrifugal chiller using this method, it is possible to achieve the recovery levels required by law without any further recovery. When recovering refrigerant from the centrifugal chiller using this method, it minimizes the risk of chiller tube freeze-up. When recovering refrigerant from the centrifugal chiller using this method, the vent hose connection should be closed. When recovering refrigerant from the centrifugal chiller using this method, it is permissible to exceed 90% of the weight capacity of the refrigerant drum. Refrigeration & Air Conditioning
B The surging that occurs in a centrifugal air conditioning compressor is a result of what conditions? low pressure in the evaporator at high load low pressure in the evaporator at low load low pressure in the condenser at high load low pressure in the condenser at low load Refrigeration & Air Conditioning
A In an air conditioning system, low discharge head pressure associated with a reciprocating compressor can be the result of what condition? leaky suction valves insufficient cooling water to the condenser air in the condenser air in the evaporator coils Refrigeration & Air Conditioning
C The amount of HCFC-123 in a storage cylinder is measured by what means? saturation pressure saturation temperature weight volume Refrigeration & Air Conditioning
C Which of the following substances is normally classified as a low pressure refrigerant? R-22 R-12 R-123 R-134A
Refrigeration & Air Conditioning
D What is the color coding for a storage container of R-134a refrigerant? green purple grey light blue Refrigeration & Air Conditioning
B The gas that exists in the stratosphere forming a protective shield that helps to protect the environment from the harmful effects ultraviolet radiation is called what? nitrogen ozone oxygen radon Refrigeration & Air Conditioning
A The "tare weight" of a refrigerant storage cylinder refers to what weight? the weight of an empty cylinder the total weight of a fully charged cylinder the weight of a cylinder AND its current contents the maximum weight of the refrigerant allowed Refrigeration & Air Conditioning
A The safety heads of most large reciprocating compressors used in refrigeration systems are held in place by what means? heavy coil springs large Teflon gaskets tack welding on the sides discharge pressure in the relief valve return line Refrigeration & Air Conditioning
A In the illustrated refrigeration system, what is the proper name for the component labeled "A"? Illustration GS-RA-12 compressor condenser accumulator filter drier Refrigeration & Air Conditioning
C A device used to hold open the refrigeration compressor suction valve during starting to reduce the compression load is called what? relief valve discharge line bypass cylinder unloader suction line bypass Refrigeration & Air Conditioning
C The carbon seal ring of a refrigeration compressor crankshaft mechanical seal is held in position against the stationary ring face by using what device? snap ring woodruff key spring thrust washer Refrigeration & Air Conditioning
B What is the drive arrangement of refrigeration compressor shown in figure "B" of the illustration? Illustration GS-RA-41 external-drive welded, fully hermetic open serviceable, bolted, accessible semi-hermetic Refrigeration & Air Conditioning
D If the discharge reed valves used in a refrigeration compressor are leaking badly, what statement is true? the reed valves should be reground and relapped the low side pressure will indicate below normal the high pressure cut-out setting should be lowered the reed valves should be replaced Refrigeration & Air Conditioning
D In addition to the drive belt itself, a V-belt that is tensioned too tight will cause excessive wear to what other drive component? the prime mover drive pulley the shaft of the prime mover the compressor drive pulley motor shaft and compressor main bearings Refrigeration & Air Conditioning
C When one belt of a multiple V-belt drive requires replacing, what will be required? season the new belt prior to installation ensure the proper belt dressing is applied replace the entire belt set ensure the seasoned belts are reinstalled in their proper sequence Refrigeration & Air Conditioning
A Excessively tight drive belts installed between a motor and a refrigeration compressor pulley may cause what condition? premature wear of both the pulley end motor shaft bearing and the pulley end compressor crankshaft main bearing due to overloading premature wear of both motor shaft bearings and both compressor crankshaft main bearings due to belt slippage premature wear of the pulley end motor shaft bearing, but normal wear of the pulley end compressor crankshaft main bearing normal wear of the pulley end motor shaft bearing, but premature wear of the pulley end compressor crankshaft main bearing Refrigeration & Air Conditioning
A When installing a mechanical shaft seal on a refrigeration compressor, extreme care must be taken to prevent what from happening? dirt and foreign particles from coming in contact with the highly polished sealing surfaces any lubricant from contacting the carbon surface that would cause the expulsion of the saturated Teflon film any lubricant from contacting the stationary seal face that would cause etching of the face surface the spring from being damaged by the corrosive effects of excessive handling Refrigeration & Air Conditioning
C If a refrigeration system were short of refrigerant, besides an elevated box temperature, what would be an observable symptom? short cycling of the compressor on the water failure switch high suction pressure continuous running of the compressor high discharge pressure Refrigeration & Air Conditioning
A A reciprocating refrigeration compressor may be tested for leaking discharge valves by stopping the compressor, turning the discharge service valve all the way in, and then turning the compressor over by hand. If the discharge valves are leaking, the compound gage will show pressures which react in which way? rising and falling with each stroke decreasing to a vacuum increasing with each stroke decreasing with each stroke Refrigeration & Air Conditioning
B Which of the conditions listed could cause excessively low refrigerant pressure at the compressor suction of a TXV controlled refrigeration system? The high pressure cutout switch is inoperative. The system is low on refrigerant. The box solenoid valve 'stuck' in the open position. Insufficient flow of condenser cooling water. Refrigeration & Air Conditioning
B Low compressor head pressure in a refrigeration system can be caused by which of the following? air in the refrigeration system excessive condenser cooling water flow excessive refrigerant in the system insufficient condenser cooling water flow Refrigeration & Air Conditioning
A An excessive charge of refrigerant in a thermostatically controlled, air-cooled, refrigeration system using a TXV as an expansion device can cause which of the following? higher than normal discharge pressure the compressor to run continuously lower than normal box temperature oil foaming in the compressor Refrigeration & Air Conditioning
C In an operating, water-cooled, multi-box refrigeration system, both low discharge and high suction pressures are being simultaneously experienced. The probable cause for this condition is which of the following? overcharge of refrigerant in the system fouled shell-and-tube condenser discharge relief valve leaking back to the suction side improper superheat adjustment on the low side Refrigeration & Air Conditioning
D If a refrigeration system, equipped with a reciprocating compressor, has a liquid-line solenoid valve that is leaking during the 'off' cycle, what would this cause? high superheat in the outlet coil refrigerant slugs in the receiver low suction pressure noisy compressor operation upon starting Refrigeration & Air Conditioning
D Unusual noise coming from a refrigeration compressor can be caused by which of the following conditions? worn bearings and piston pins too much oil in circulation slugging due to flooding back All of the above. Refrigeration & Air Conditioning
C Which of the listed statements describes the reason why oil foaming occurs when starting a refrigeration compressor? This phenomenon is inherent only in hermetically sealed units and is always provisional. This will occur only if crankcase heaters are used. This condition is the result of the sudden low pressure created in the crankcase at start up causing the release of refrigerant absorbed within the oil. If the oil level is not initially high, this condition is the result of agitation created by the
movement of the mechanical components.
Refrigeration & Air Conditioning
C A refrigeration unit will tend to short cycle when operating under what conditions? under heavy loads during starting conditions lack of refrigerant during hot gas defrost Refrigeration & Air Conditioning
C If a refrigeration compressor were short cycling on the low pressure cutout switch, what is the most probable cause? the high pressure switch was improperly adjusted the system was overcharged with refrigerant the expansion valve strainers were fouled the suction valves were leaking slightly Refrigeration & Air Conditioning
B A box solenoid valve used in a multi-box refrigeration system is operated by electromagnetic action by what control device? evaporator outlet temperature actuated thermostat box temperature actuated thermostat discharge pressure actuated pressure switch suction pressure actuated pressure switch Refrigeration & Air Conditioning
C What is the purpose of the low pressure cut-out switch as used as a primary controller for a refrigeration system or unit? maintain a preset low-side pressure for the system control the capacity of the compressor start and stop the compressor as needed maintain a preset suction pressure to the compressor Refrigeration & Air Conditioning
D The sensing line for the low pressure cutout switch for a refrigeration system is typically connected at what location? at the outlet side of the receiver at the discharge side of the compressor at the inlet side of the receiver at the suction side of the compressor Refrigeration & Air Conditioning
C Which of the listed operations will cause an automatically controlled refrigeration compressor to restart if the system features a pump-down cycle? Decreasing the suction pressure Closing of the expansion valve An increase in the suction pressure Closing of the solenoid valve Refrigeration & Air Conditioning
A The low pressure cutout switch settings vary with the refrigerant used and the temperature application. If the low pressure cutout switch for a particular application is set with a cut-in pressure of 5 psig, what would be the cut-out pressure if the differential is 7.5 psig? 5" Hg 0 psig 2.5 psig 12.5 psig Refrigeration & Air Conditioning
D In a multi-evaporator refrigeration system, a solenoid valve is installed in the liquid line prior to what device? the condenser the receiver the oil separator each expansion valve Refrigeration & Air Conditioning
B A liquid line solenoid valve controls refrigerant flow to the evaporator by what means? sensing the temperature in the liquid line fully opening or closing throttling the refrigerant sensing the superheat in the tail coil Refrigeration & Air Conditioning
A How does a refrigeration solenoid valve differ from a modulating valve? A liquid line solenoid valve is either completely opened or closed, whereas a modulation valve is infinitely positioned according to the strength of the applied electrical signal. Both valves operate in exactly the same manner, only the manufacturer's terminology is the differentiating factor. A solenoid valve can only be installed in liquid lines. Solenoid Valves are only used in low voltage refrigeration control systems, while modulation valves are used in high voltage applications. Refrigeration & Air Conditioning
A Which of the following electrically operated refrigeration system valves would be most appropriate for use as a 2 position diverting hot gas bypass solenoid valve? Illustration GS-RA-19 B D A C Refrigeration & Air Conditioning
B In a refrigeration system featuring low-side pump down prior to the automatic shut down of the compressor, the temperature of the refrigerated space is controlled by the action of a thermostat wired to what device? suction line solenoid liquid line box solenoid low pressure cutout switch thermostatic expansion valve Refrigeration & Air Conditioning
D The thermostat controlling the operation of the solenoid valve to a refrigerated box evaporator senses what temperature? evaporator coil outlet temperature compressor discharge temperature evaporator coil inlet temperature the refrigerated box temperature Refrigeration & Air Conditioning
B Which of the following statements is true? Illustration GS-RA-12 Valve "14" is the king solenoid, valve "36" is the chill box solenoid, and valve "28" is the freeze box solenoid. Valve "14" is the king solenoid, valve "28" is the chill box solenoid, and valve "36" is the freeze box solenoid. Valve "14" is the king solenoid, valves "28" and "36" are both freeze box solenoids. Valve "14" is the king solenoid, valves "28" and "36" are both chill box solenoids. Refrigeration & Air Conditioning
A A container unit's microprocessor-controlled temperature controller is set at -28.9 C, appropriate for a frozen cargo of ice cream. In this mode of operation, according to the illustrated temperature controller functional diagrams, what should be the operational status of the unit if the actual box temperature is -18.0 C? Illustration GS-RA-35 cooling mode modulating cooling mode air circulation mode heating mode Refrigeration & Air Conditioning
D Capacity control of a centrifugal refrigeration compressor can be accomplished by what means? varying the speed of the compressor varying the position of the suction inlet damper vanes varying the position of the hot gas bypass valve All of the above. Refrigeration & Air Conditioning
B The fluid used as a source of actuating power against the underside of the unloader power element piston of the refrigeration compressor capacity control mechanism illustrated is obtained from where? Illustration GS-RA-13 gas discharge from the compressor discharge of the compressor lube oil pump high side liquid receiver discharge of a secondary hydraulic pump specifically installed for this operation Refrigeration & Air Conditioning
C During operating periods of a multi-box refrigeration system using a capacity controlled compressor, when all of the evaporators of a four box plant are actively being fed with liquid refrigerant, the control oil pressure acting on the hydraulic relay piston will be at what value? GS-RA-13 the lowest at its mid-range the highest of no consequence as the lube oil is not used in the operation of the unloader Refrigeration & Air Conditioning
B A refrigeration compressor used in a multi-box refrigeration system, is designed with six of its eight cylinders able to be controlled for variable load conditions. If all of the reefer boxes are currently feeding, what percentage of the total number of compressor cylinders will be loaded after start up? 25 (%) 100 (%) 50 (%) 0 (%) Refrigeration & Air Conditioning
C On a modern refrigerated container unit employing suction modulation for the purposes of capacity control and capacity limitation, what happens when the applied voltage and current draw associated with the normally open (NO) suction modulation valve located in the suction line both increase? the valve will further open, lowering evaporator pressure and raising suction pressure the valve will further open, raising evaporator pressure and lowering suction pressure the valve will further close, raising evaporator pressure and lowering suction pressure the valve will further close, lowering evaporator pressure and raising suction pressure Refrigeration & Air Conditioning
A To prevent motor overload during start-up of a hermetically sealed centrifugal refrigeration system, what is true concerning the compressor suction gas variable inlet guide vanes? closed until the motor is connected across the line at full voltage and current drawn is below full load current opened until the motor is connected across the line at full voltage and current drawn is up to full load current closed until the motor is connected across the line at full voltage and current drawn is up to full load current opened until the motor is connected across the line at full voltage and current drawn is below full load current Refrigeration & Air Conditioning
B As shown in the illustrated refrigeration system piping schematic diagram with the various accessories and controls and equipped with an air-cooled condenser with high side pressure controls, what statement is true concerning the fan cycling control pressure switch? Illustration GS-RA-39 With a condenser fitted with a single fan driven by a multi-speed electric motor, the fan speed would decrease under high ambient temperature conditions. With a condenser fitted with a single fan driven by a multi-speed electric motor, the fan speed would decrease under low ambient temperature conditions. With a condenser fitted with multiple electric-motor driven fans, the number of fans in use would increase under low ambient temperature conditions. With a condenser fitted with a single fan driven by a single-speed electric motor, the fan would cycle off under high ambient temperature conditions. Refrigeration & Air Conditioning
C If it is necessary to increase the operating head pressure of the refrigeration system using the device shown in the illustration, what should be done? Illustration GS-RA-14 "2" should be turned to relax the compression of the spring "4" should be rotated to compress the enclosed bellows "2" should be turned to further compress the spring "4" should be rotated to relax the enclosed bellows Refrigeration & Air Conditioning
D In a refrigeration system, the valve shown in the illustration is used for what purpose? Illustration GS-RA-14 thermostatic expansion valve suction pressure regulating valve evaporator pressure regulating valve head pressure regulating valve Refrigeration & Air Conditioning
A The set point adjustment of the device shown in the illustration is made by rotating what component? Illustration GS-RA-14 "2" "3" "4" "1" Refrigeration & Air Conditioning
C An arrow stamped on the valve body of a water regulating valve indicates which of the following? closed position direction of the plunger slide direction of the flow open position Refrigeration & Air Conditioning
B During the initial cooling down of a box temperature in a refrigeration system, which of the devices listed is used to prevent excessive gas pressure at the compressor suction for the purpose of prevention of overloading of the compressor driver? High pressure cutout Crankcase pressure regulator Low pressure cutout Solenoid valve Refrigeration & Air Conditioning
D The rupture disc on a low pressure centrifugal refrigeration unit is used as an over pressure protection device and is set to relieve at 15 psig and is most likely to lift when the compressor is idle? Where is the rupture disc located? on top of the condenser shell at the top of the upper chamber of the economizer at the discharge of the compressor on top of chiller evaporator shell Refrigeration & Air Conditioning
D Which of the lettered components shown in the illustration indicates the high-pressure cut-out? Illustration GS-RA-12 Z W Y X Refrigeration & Air Conditioning
D When the relief valve opens on a refrigeration compressor discharge line, it discharges high pressure refrigerant vapor to what location? refrigerant inlet of the condenser liquid strainer inlet side of the evaporator suction side of the compressor Refrigeration & Air Conditioning
C In a refrigeration system that is not protected by a water failure switch, if the cooling water to the condenser fails, what will be the result for protective purposes? the king valve will open the box temperature solenoid valve will close initiating a pump down the compressor will shut down by the action of the high pressure cutout switch the expansion valve will close due to high superheat Refrigeration & Air Conditioning
A The receiver used in a refrigeration system performs what essential function? holds the entire refrigerant charge after system pump down collects air and non-condensable gases prevents liquid refrigerant from flooding back to the compressor allows the refrigerant to be superheated Refrigeration & Air Conditioning
D In a large refrigeration system having more than one evaporator, a king solenoid valve should be installed in what location? before the condenser between the condenser and receiver before the back pressure regulating valve just after the receiver Refrigeration & Air Conditioning
B If the valve labeled "D" in the illustration is a suction service valve, what will the port labeled "7" be connected to? Illustration RA-0008 to the inlet of the compressor to the line connected to the evaporator outlet to the line connected to the evaporator inlet to the outlet of the compressor Refrigeration & Air Conditioning
C Refrigeration system isolation valves are specially designed with a back-seat, as well as a front-seat. For what purpose are these valves designed in this way? allow for operation as a suction or discharge valve allow for removal and replacement of the valve without shutting down permit repacking the valve stem under pressure without shutting down allow for operation as a liquid or vapor valve Refrigeration & Air Conditioning
D In addition to the indicated gauge pressure, what other information is presented on the compound gauge for the hypothetical refrigerant illustrated? Illustration GS-RA-16 the absolute pressure of the refrigerant at the point of measurement the actual temperature of the refrigerant at the point of measurement the metric pressure equivalent of the refrigerant at the point of measurement the saturation temperature of the refrigerant that corresponds to the gauge pressure at the point of measurement Refrigeration & Air Conditioning
B Which lettered component, shown in the illustration, indicates the location of the receiver? Illustration GS-RA-12 A C F B Refrigeration & Air Conditioning
A In a refrigeration plant, what is one vital purpose of the receiver? store the refrigerant charge superheat the refrigerant liquid cool the refrigerant gas condense the refrigerant Refrigeration & Air Conditioning
D As shown in the illustrated LP centrifugal chiller pressure maintenance system, what is its functional purpose? Illustration GS-RA-40 prevent surging maintain a relatively low compression ratio under low heat load conditions prevent the entrance of air into the chiller under low heat load conditions prevent the entrance of air into the chiller when the chiller is idle Refrigeration & Air Conditioning
A What is the purpose of the pressure transducer as shown in the illustration? Illustration GS-RA-17 it senses compressor suction pressure and controls the quench valve it senses compressor discharge pressure and controls the suction modulation valves it senses compressor suction pressure and controls the suction modulation valves it senses compressor discharge pressure and controls the quench valve Refrigeration & Air Conditioning
D In addition to pressure, most compound and standard pressure gauges used for refrigeration service are also provided with a scale indicating what parameter? absolute pressure sub cooled refrigerant temperature superheated refrigerant temperature saturated refrigerant temperature Refrigeration & Air Conditioning
A Hard drawn copper tubing is commonly used in larger refrigeration systems. What statement concerning its use is true? Hard drawn copper tubing is not easily flared, bent, or swaged, so brazed fittings are
commonly used.
Hard drawn copper tubing is easily swaged, so reducing fittings are rarely used in changing line size. Hard drawn copper tubing is easily bent, so elbow fittings are rarely used in changing
direction.
Hard drawn copper tubing is easily flared, so flare fittings are commonly used. Refrigeration & Air Conditioning
C In a refrigeration system, what component is installed directly downstream of the thermal expansion valve? box solenoid valve receiver evaporator coil compressor Refrigeration & Air Conditioning
C Refrigeration systems using forced air circulation evaporators have a tendency to cause rapid dehydration of produce in chill boxes. Which of the following will minimize this dehydration? the air is circulated rapidly over a small evaporator with a maximum temperature differential o the air is circulated rapidly over a small evaporator with a minimum temperature differential the air is circulated slowly over a large evaporator with a minimum temperature differential the air is circulated slowly over a large evaporator with a maximum temperature differential Refrigeration & Air Conditioning
D In a dry-type direct expansion refrigeration evaporator, what is true concerning the evaporator coils? the coils are covered on the outside with insulation the coils are coated on the inside with insulation the coils are surrounded on the outside by refrigerant the coils are surrounded on the outside by air Refrigeration & Air Conditioning
C Zinc plates commonly found in refrigeration systems and used as sacrificial anodes are located where? refrigerant side of the condenser cooling water suction strainer saltwater side of the condenser evaporator coils Refrigeration & Air Conditioning
B Seawater or low temperature central fresh water is typically provided to a ship's stores refrigeration plant for what purpose? prevent motor overheating condense the refrigerant gas cool the expansion valve prevent refrigerant superheating Refrigeration & Air Conditioning
B Heat is removed from the refrigerant circulating through the refrigeration system, shown in the illustration, by which component? Illustration GS-RA-12 A B J K Refrigeration & Air Conditioning
B If a condenser coil of an air-cooled container refrigeration system becomes dirty and requires cleaning, what would be an acceptable method of cleaning? Binks' gun with weak acid solvent high pressure water wash copper wire rotary brush All of the above. Refrigeration & Air Conditioning
A When checking zinc plates, or pencil Zincs in the refrigerating system condenser, what should you do? replace the Zincs if deteriorated by 50% renew the plates at each inspection file the plates to change the negative value paint and insulate the plates to prevent corrosion Refrigeration & Air Conditioning
A What is true concerning the accumulation of air and other non-condensable gases in a refrigeration system? collect in the condenser create a vapor lock in the liquid receiver cause a loss of the liquid seal cause foaming of the oil in the crankcase Refrigeration & Air Conditioning
B Through which of the components shown in the illustration is flash gas formation a normal occurrence? Illustration GS-RA-25 evaporator coil thermostatic expansion valve receiver tank condenser coil Refrigeration & Air Conditioning
C In a refrigeration system, the pressure within the power element of a thermostatic expansion valve depends directly upon what factor? compressor suction pressure temperature in the box temperature of the evaporator coil outlet heat transferred from the saturated liquid in the evaporator Refrigeration & Air Conditioning
A In a refrigeration system, the bulb for the thermal expansion valve is always located where? at the evaporator coil outlet in the middle of the evaporator coils at the evaporator coil inlet at the beginning of the bottom row of the evaporator coils Refrigeration & Air Conditioning
A Concerning the proper installation of the sensing bulb of a thermal expansion valve that is attached to the evaporator tail coil on a horizontal run, what statement is true? the bulb should be attached so that the pinched off tubing should be oriented down and the capillary tube running to the valve diaphragm should be oriented up the bulb should be attached with no regard to the orientation of the pinched off tubing or the capillary tube running to the valve diaphragm the bulb should be attached so that the pinched off tubing should be oriented up and the capillary tube running to the valve diaphragm should be oriented down the bulb should be attached so that the pinched off tubing should be oriented to one side and the capillary tube running to the valve diaphragm should be oriented to the opposite side Refrigeration & Air Conditioning
D Which of the statements listed is applicable to the thermostatic expansion valve shown in the illustration? Illustration GS-RA-07 It regulates the temperature of the refrigerated space. It regulates the amount of superheat at the solenoid valve. The external equalizing pipe is connected to the liquid receiver. The control bulb is located on the evaporator coil outlet. Refrigeration & Air Conditioning
A When the sensing bulb of a thermostatic expansion valve is charged with a fluid different from the charge used in the system, what name of the charge is associated with the power element? cross charged blended charged straight charged mixed charged Refrigeration & Air Conditioning
D A typical shipboard domestic multi-box refrigeration system operates with one compressor and condenser. What is the purpose of the sensing line connected to the thermal bulb at the evaporator coil outlet? To direct evaporator outlet pressure to the lower part of the solenoid bellows. To open or close the solenoid valve when the box temperature increases or decreases. To open the back-pressure regulating valve when evaporator coil pressure increases. To transmit the bulb pressure (proportional to the coil temperature) to the thermal expansion valve diaphragm. Refrigeration & Air Conditioning
B Refrigerant flow through a thermostatic expansion valve is greatest under what conditions? when the low side and high side pressures are equal when the evaporator has just begun feeding at relatively high box temperature when the low side pressure and the bulb pressure are equal just before the evaporator stops feeding at relatively low box temperature Refrigeration & Air Conditioning
C In a vapor compression type refrigeration cycle, the refrigerant temperature decreases the most when passing through which system component? evaporator compressor expansion valve condenser receiver Refrigeration & Air Conditioning
A The thermostatic expansion valve in a refrigeration system further opens when the diaphragm flexes downward. With all other conditions being the same, what single condition causes this? an increase in sensing bulb temperature an increase in the evaporator pressure a decrease in sensing bulb temperature increasing the superheat setting of the valve Refrigeration & Air Conditioning
D In refrigeration systems with multiple evaporators, the metering of refrigerant to each refrigerated space evaporator is accomplished by what device? the individual back pressure regulating valves the King valve the individual box Solenoid Valves the individual thermal expansion valves Refrigeration & Air Conditioning
C In the multi-evaporator refrigeration system shown in the illustration, what is the proper name for the valve labeled "29"? Illustration GS-RA-12 chill box evaporator pressure regulating valve freeze box thermostatic expansion valve chill box thermostatic expansion valve chill box solenoid valve Refrigeration & Air Conditioning
D Rather than design an infinite variety of thermostatic expansion valve sizes to accommodate different capacities for heat removal, some manufacturers use a few standard valve body sizes in conjunction with what other feature? a flexible diaphragm to accommodate different heat removal capacities an externally adjustable superheat to accommodate different heat removal capacities internal equalizers to accommodate different heat removal capacities internal needle valve orifices of various sizes to accommodate different heat removal
capacities
Refrigeration & Air Conditioning
C Constant superheat is maintained at the evaporator coil outlet of a refrigeration system or unit by the action of what device? king valve low pressure cutout switch thermal expansion valve solenoid valve Refrigeration & Air Conditioning
A Besides the evaporator pressure, the thermal expansion valve reacts directly to changes in what parameter? temperature of the evaporator coil outlet temperature of the space being cooled liquid refrigerant pressure at the solenoid valve pressure drop across the evaporator coils Refrigeration & Air Conditioning
C Which of the following illustrated expansion valves is designed to maintain a constant evaporator pressure rather than a constant evaporator superheat? Illustration GS-RA-24 A D C B Refrigeration & Air Conditioning
C Which of the following illustrated thermal expansion valves would be appropriate to use on an evaporator coil with a 2 psi pressure drop, where externally adjustable superheat and a replaceable power element are both desired? Illustration GS-RA-06 D C B A Refrigeration & Air Conditioning
B What is one function of the thermal expansion valve used in a refrigeration system? turn the compressor off and on regulate the amount of refrigerant flow to the evaporator coil act as a pilot controlling the box solenoid valve regulate the water flow to the water-cooled condenser Refrigeration & Air Conditioning
D When a refrigeration compressor is in the 'off' cycle, the thermal expansion valve will react in what way? it will always completely close regardless of whether or not the system employs a pump down cycle it will always open wide regardless of whether or not the system employs a pump down cycle it will always remain in the same position just prior to the cycling off of the compressor it will continue to function as a result of the net balance of forces acting on the diaphragm Refrigeration & Air Conditioning
C Of the various possible methods shown in the illustration, which is the correct method of attaching a TXV feeler bulb to a large line (7/8" and larger) with a horizontal run? Illustration GS-RA-50 A B C D Refrigeration & Air Conditioning
A When a thermostatic expansion valve is installed in a refrigerated container unit, the sensing bulb almost always requires insulation. Why is this so? the insulation prevents air stream temperatures from influencing the bulb temperature the insulation protects the clamp and screws from corrosion the insulation prevents the bulb from vibrating loose the insulation prevents oil entrained in the suction gas from influencing the bulb temperature Refrigeration & Air Conditioning
D Which of the following statements describes the accepted method for testing a thermostatic expansion valve? Chill the bulb in ice water while observing the compressor for an increase in suction pressure. Remove the power head from the unit, heat the bulb with a torch while using a scale to measure the distance the diaphragm has moved. Heat the bulb by using a halide torch or similar device and observe the valve stem movement. Place the sensing bulb in ice water and then warm by hand. Observe flood-through and temperature change at the suction line. Refrigeration & Air Conditioning
C The coil temperature measured at the expansion valve sensing bulb of an operating system is 10F. The low side pressure with the compressor running as shown on the gauge illustrated indicates 15 psig. What adjustments or changes, if any, should be made to the system? Illustration GS-RA-16 The evaporator coils need to be steam cleaned or high pressure washed. The liquid line strainer is obviously fouled and needs to be cleaned. The expansion valve should not be adjusted, as the degree of superheat is within the
accepted range.
The filter drier needs to be changed to increase the suction pressure. Refrigeration & Air Conditioning
A Concerning the proper installation of the sensing bulb of a thermal expansion valve that is attached to the evaporator tail coil on a horizontal run, which statement is true? the bulb should be attached so that the pinched off tubing should be oriented down and the capillary tube running to the valve diaphragm should be oriented up the bulb should be attached so that the pinched off tubing should be oriented to one side and the capillary tube running to the valve diaphragm should be oriented to the opposite side the bulb should be attached with no regard to the orientation of the pinched off tubing or the capillary tube running to the valve diaphragm the bulb should be attached so that the pinched off tubing should be oriented up and the capillary tube running to the valve diaphragm should be oriented down Refrigeration & Air Conditioning
D A thermostatic expansion valve is properly controlling evaporator superheat. Adjusting this valve to lower the evaporator superheat setting will result in which of the following? the expansion valve will further close the expansion valve diaphragm will rupture the evaporator pressure will decrease the evaporator feed will increase Refrigeration & Air Conditioning
B When replacing a thermostatic expansion valve power element, what is true concerning the thermal bulb? apply a heavy coating of grease to function as a heat sink with steel wool or an abrasive cloth remove oxidation on the bulb and suction line apply a light film of oil to increase heat transfer carefully coat the device with silicone sealant to reduce the effects of convective cooling Refrigeration & Air Conditioning
B If the evaporator coil horizontal return line of a container refrigeration system is less than 0.875" (2.21 cm) in diameter (considered small), the thermostatic expansion valve sensing bulb should be attached where on the return line? as close as possible to the expansion valve on the upper surface of the line on the bottom of the line to enable the bulb to absorb the maximum amount of heat directly below the point of maximum heat transfer Refrigeration & Air Conditioning
D Expansion valve maintenance should include which of the following procedures? Cleaning of in-line strainers as necessary. Ensuring that the thermal bulb is in good contact with the suction line and insulated. Checking that the thermal bulb is in the proper location. All of the above. Refrigeration & Air Conditioning
D Which statement about calibrating a newly installed thermostatic expansion valve is correct? This procedure is done at the factory with tools not available to a mariner. No special tools are required as long as the solid state circuit control panels are functioning properly. The procedure requires a refrigeration wrench and a digital thermometer to measure box


temperature.
An accurate thermometer and suction pressure gage are essential to this process. Refrigeration & Air Conditioning
C Which of the installation steps listed is necessary for the proper operation of the thermostatic expansion valve? Remove excess lengths of the sensing bulb capillary tube from the device to increase
sensitivity.
Attach the thermal bulb to the suction line using plastic ties. Clean off oxidation from the surface of the suction line and sensing bulb with fine abrasive cloth or steel wool. Heat shrink insulating material around the device once the bulb has been properly secured. Refrigeration & Air Conditioning
D Which of the listed statements describes the method used to determine the amount of superheat present in the suction gas leaving the evaporator coil? Illustration GS-RA-16 Note the low side pressure, determine the corresponding saturation temperature, and subtract it from the temperature measured with a thermometer at the compressor suction inlet. Subtract the temperature measured at the thermostatic expansion valve sensing bulb from the saturation temperature corresponding to the low side pressure. Note the low side pressure, determine the corresponding saturation temperature, and add it to the temperature measured with a thermometer at the thermostatic expansion valve sensing bulb. Note the low side pressure, determine the corresponding saturation temperature, and subtract it from the temperature measured with a thermometer at the thermostatic expansion valve sensing bulb. Refrigeration & Air Conditioning
C What maintenance may be carried out on a thermostatic expansion valve? The thermal bulb may be recharged. The proportional action may be varied. The inlet screen may be cleaned. The rate action may be increased. Refrigeration & Air Conditioning
B Which of the following conditions will occur if the power element of the thermostatic expansion valve shown in the illustration loses its charge? Illustration GS-RA-07 The valve will begin to close, but the external equalizing line will assist in keeping the valve

unseated.
The valve will fail closed, providing no cooling capacity. The valve will fail open and the cooling capacity will be increased. The valve will fail open as designed to provide continuous cooling. Refrigeration & Air Conditioning
D If the superheat setting of a thermostatic expansion valve is set too low, what would be the result, assuming that the system has a single evaporator? the box temperature will be pulled way down below the normal temperature range the receiver level will be abnormally high due to a reduced amount of refrigerant returning back to the compressor the suction line will be abnormally warm due to a reduced amount of refrigerant returning back


to the compressor
the suction line will be abnormally cold and liquid may flood back to the compressor Refrigeration & Air Conditioning
B If the superheat value of the thermostatic expansion valve is adjusted too high, what would be the result? the heat removal capacity of the evaporator will increase the suction line of the compressor will be abnormally warm the evaporator will be overfed with liquid refrigerant the suction line of the compressor will be abnormally cold Refrigeration & Air Conditioning
C A small obstruction at the thermostatic expansion valve inlet will result in which of the following conditions? Higher than normal discharge pressure. Expansion valves are designed to pass small foreign particles so no adverse condition will

occur.
Lower than normal suction pressure. Ice is the sole cause of this and will soon melt due to superheat; no adverse condition will occur. Refrigeration & Air Conditioning
A An obstructed expansion valve may be indicated by an incompletely cooled evaporator and what other symptom? frosting at the evaporator inlet frosting at the suction side of the compressor a higher than normal discharge pressure a decrease in the amount of frosting across the drier Refrigeration & Air Conditioning
A If the needle and seat assembly is excessively eroded, the valve cage assembly can be replaced. In replacing the original valve cage assembly rated at 1/2 tons, what would be the result if the replacement valve cage was oversized at 5 tons? Illustration GS-RA-07 The expansion valve would hunt excessively, alternately starving and overfeeding the
evaporator coil.
The expansion valve would function normally, with the presentation of no problems. The evaporator would be overfed producing consistently insufficient superheat. The evaporator would be starved producing consistently excessive superheat. Refrigeration & Air Conditioning
D Vapor bubbles present in the liquid upon arrival to the thermal expansion valve in a refrigeration system may cause erosion of the expansion valve's needle and seat. This, in turn, could cause what condition? TXV freezing open TXV overheating TXV freezing shut TXV hunting Refrigeration & Air Conditioning
B Moisture entering a typical refrigeration system will most likely produce what effect? boil in the condenser freeze in the expansion valve be removed by the liquid line strainers cause sweating and frost on the evaporator coils Refrigeration & Air Conditioning
D Concerning the operation of refrigeration systems, frosting or sweating of a liquid line is usually indicative of what condition? proper cooling taking place high relative humidity surrounding the liquid line the refrigerant contaminated with moisture a liquid line restriction Refrigeration & Air Conditioning
D An air-cooled refrigerated container unit using R-134a as a refrigerant has a box temperature set point of -15 F, but it is currently operating with a stable return air temperature of 0 F. The fresh air makeup vent is closed, the unit is operating at 460 VAC/60 Hz, and the unit is in full capacity cool (modulating valve 100% open). Using the illustrated troubleshooting guide, what would be the normal range of expected discharge pressures if the ambient air temperature is 90 F? Illustration GS-RA-52 190-230 psig 200-220 psig 160-180 psig 150-190 psig Refrigeration & Air Conditioning
B If increasing the cooling water flow to a refrigeration condenser fails to lower the condenser pressure, the probable cause may be due to what condition? partially blocked thermal expansion valve excessive amount of non-condensable gases trapped in the condenser an evaporator coil in need of defrosting a low level of Freon in the receiver Refrigeration & Air Conditioning
D Which of the conditions listed could cause excessively low refrigerant pressure at the compressor suction of a TXV controlled refrigeration system? The box solenoid valve 'stuck' in the open position. Insufficient flow of condenser cooling water. The high pressure cutout switch is inoperative. The system is low on refrigerant. Refrigeration & Air Conditioning
C In an operating, water-cooled, multi-box refrigeration system, both low discharge and high suction pressures are being simultaneously experienced. The probable cause for this condition is which of the following? fouled shell-and-tube condenser improper superheat adjustment on the low side discharge relief valve leaking back to the suction side overcharge of refrigerant in the system Refrigeration & Air Conditioning
C High suction pressure accompanied by low suction temperature to a refrigeration system compressor is caused by which of the following? a clogged liquid-line strainer the expansion valve is insufficiently opened the expansion valve being open too wide the king valve is insufficiently open Refrigeration & Air Conditioning
D Low compressor head pressure in a refrigeration system can be caused by which of the following? excessive refrigerant in the system insufficient condenser cooling water flow air in the refrigeration system excessive condenser cooling water flow Refrigeration & Air Conditioning
D If the running suction pressure at the refrigeration compressor of a TXV controlled air-cooled refrigeration system is below normal, which of the following can be a cause? overfeeding by the expansion valve a dirty condenser refrigerant overcharge a restricted liquid-line strainer Refrigeration & Air Conditioning
C During tests to discover why a refrigeration compressor is running continuously, it is determined that the refrigerated space temperature is slightly above normal without ever reaching the desired minimum temperature. Suction and discharge pressures are normal for the corresponding box temperature. In this situation, what should you suspect? high cooling water temperature a shortage of refrigerant leaking door gaskets air in the system Refrigeration & Air Conditioning
D If a refrigeration compressor using a thermostat as a primary controller is running continuously without significantly lowering the temperature in the refrigerated space, which of the following is most likely the trouble? excessive condenser cooling water warm food in the refrigerator a shortage of compressor oil a shortage of refrigerant Refrigeration & Air Conditioning
D Moisture in a refrigeration system can cause which of the following conditions? freezing the expansion valve closed corrosion of system piping hermetic motor burnout All of the above. Refrigeration & Air Conditioning
B Excessive moisture being collected in the purge unit of a low pressure refrigeration system could indicate which probable condition? improper charging of refrigerant leaking condenser or chiller tubes low efficiency purge unit dryer core needs replacement Refrigeration & Air Conditioning
C An evaporator coil of a single evaporator, air cooled refrigerator is accumulating excessive frost due to a failure of the defrost mechanism. If the refrigerator features a thermostatically controlled box solenoid and a low pressure cutout controlled compressor, as well as a high pressure cutout, in terms of the compressor, what would be the most likely operating symptom? run continuously fail to start short cycle on low pressure cutout short cycle on high pressure cutout Refrigeration & Air Conditioning
B In a low pressure refrigeration system, excessive running of the purge recovery unit generally indicates which probable condition? overcharged system system leaks on the low side faulty purge system vent valve system leaks on the high side Refrigeration & Air Conditioning
C The compressor on the ships service refrigeration system starts up but stops after a brief period of running. Subsequent attempts to start it produce no result. What control component would you suspect? The water regulating valve. The high pressure cut out. The lube oil differential pressure switch. The back pressure regulator. Refrigeration & Air Conditioning
D While troubleshooting intermittent failures of the ship service refrigeration system you suspect the problem is with the lube oil pressure differential switch. The recommended course of action would be: Decrease the time delay setting and see if problem persists. Increase the switch setting and see if problem persists. Lower the switch setting and see if problem persists. Replace the switch as there is generally no adjustments available on the switch. Refrigeration & Air Conditioning
A When a refrigeration compressor motor fails to start, the FIRST thing that should be checked for is what? blown fuse or tripped circuit breaker in the motor circuit loose expansion valve control bulb faulty suction pressure regulator low differential setting on the H.P. cutout Refrigeration & Air Conditioning
D If the refrigeration compressor crankcase is sweating or frosting and is operating with an unusual noise, what is most likely the cause? the compressor short cycling on the high pressure cutout the compressor running continuously a shortage of refrigerant liquid refrigerant returning to the compressor Refrigeration & Air Conditioning
C If a refrigeration system were short of refrigerant, besides an elevated box temperature, what would be an observable symptom? short cycling of the compressor on the water failure switch high suction pressure continuous running of the compressor high discharge pressure Refrigeration & Air Conditioning
A If a refrigeration compressor were short cycling on the low pressure cutout switch, what is the most probable cause? the expansion valve strainers were fouled the high pressure switch was improperly adjusted the system was overcharged with refrigerant the suction valves were leaking slightly Refrigeration & Air Conditioning
C If a refrigeration system, equipped with a reciprocating compressor, has a liquid-line solenoid valve that is leaking during the 'off' cycle, what would this cause? high superheat in the outlet coil refrigerant slugs in the receiver noisy compressor operation upon starting low suction pressure Refrigeration & Air Conditioning
A A refrigeration unit will tend to short cycle when operating under what conditions? lack of refrigerant during starting conditions under heavy loads during hot gas defrost Refrigeration & Air Conditioning
B If a refrigeration compressor had developed a slightly high suction pressure accompanied with an abnormally low suction temperature, the problem could be a result of which of the following? a clogged sub cooler liquid refrigerant flooding back from the cooling coil a minor accumulation of air or non-condensable gases in the system a leaking king valve Refrigeration & Air Conditioning
C An excessive charge of refrigerant in a thermostatically controlled, air-cooled, refrigeration system using a TXV as an expansion device can cause which of the following? the compressor to run continuously oil foaming in the compressor higher than normal discharge pressure lower than normal box temperature Refrigeration & Air Conditioning
B Which recovery procedure should be used to minimize the loss of oil from the system during the recovery of refrigerant from small appliances such as a water cooler? initial recovery vapor recovery liquid recovery vapor-liquid recovery Refrigeration & Air Conditioning
D What is true concerning highly contaminated refrigerant recovered from burned out small appliances? The recovered refrigerant may be blended with new refrigerant for eventual re-use. The recovered refrigerant must be destroyed by the refrigeration technician. The recovered refrigerant may be used to clean out systems that have suffered from a burn


out.
The recovered refrigerant should be sent to a designated reclamation facility for processing. Refrigeration & Air Conditioning
B Technicians servicing small refrigeration appliances can employ what type of recovery equipment? do not need to recover the refrigerant either active or passive passive only active only Refrigeration & Air Conditioning
B If passive recovery is used on a small appliance fitted with a capillary tube as a metering device with a non-operating compressor, the recovery should be made through what means? by venting to atmosphere, cannot be recovered recovery from both the high and low sides recovery from the high side only recovery from the low side only Refrigeration & Air Conditioning
D Minor repairs may be performed on low pressure refrigerant systems without recovering the refrigerant charge if the pressure in the system is raised to atmospheric. How may this be accomplished? pressurize the system with nitrogen open the system vent to the atmosphere and allow the pressure to equalize charge the system until it is completely filled with liquid refrigerant heat the refrigerant Refrigeration & Air Conditioning
D The most cost-effective method of recovering refrigerant from a low pressure chiller with more than 500 lbs of refrigerant and to meet EPA requirements is to recover the refrigerant using what protocol? recovery using a vacuum pump based vapor recovery machine only vapor recovery using a vacuum pump based recovery unit followed by liquid recovery using a liquid pump recovering using a liquid pump only liquid recovery using a liquid pump, followed by vapor recovery using a vacuum pump based recovery unit Refrigeration & Air Conditioning
B Why is a purge recovery unit typically fitted on low pressure centrifugal chillers? low pressure chillers are routinely opened for maintenance thus introducing air at each opening such a chiller can operate at a pressure below atmospheric pressure on the low side thus drawing in air through any low-side leaks low pressure chillers use extremely low boiling point refrigerants evacuation of the air from a low pressure chiller prior to charging with refrigerant is not
possible
Refrigeration & Air Conditioning
D As shown in the illustrated flow diagram for a self-contained recovery unit designed for the recovery of refrigerants from high pressure appliances as defined by the EPA Clean Air Act rules, what is the functional purpose of the item labeled "FS2"? Illustration GS-RA-32 It automatically shuts down the recovery unit compressor when the recovery cylinder becomes 80% full. It automatically shuts down the recovery unit compressor when the discharge pressure becomes excessive. It automatically shuts down the recovery unit compressor when the refrigeration system has reached a depth of 15" Hg. It automatically transitions the recovery unit from the direct liquid recovery mode to the direct vapor recovery mode. Refrigeration & Air Conditioning
C How should small appliances with less than three pounds of refrigerant be charged with refrigerant? liquid charged initially liquid charged and then topped with a vapor charge vapor charged either vapor or liquid charged Refrigeration & Air Conditioning
C Charging liquid HCFC-123 into a system under a deep vacuum could cause what to happen unless necessary precautions are taken? rupture disk to rupture air and moisture to enter the receiver system secondary refrigerant to freeze the purge unit to operate Refrigeration & Air Conditioning
C When a refrigeration system is being topped off with a small amount of refrigerant through the low side with the compressor running, what should be done? the discharge service valve must be front seated the refrigerant charging cylinder should be turned upside down the refrigerant should be charged into the system as a vapor the suction service valve must be back seated Refrigeration & Air Conditioning
C Which of the valves listed is normally closed when charging the refrigeration system through the high side? Dehydrator inlet valve Thermal expansion valve Liquid line king valve Suction line valve Refrigeration & Air Conditioning
A Using the device shown in the illustration, which of the following statements is true when adding refrigerant as a vapor to the low side of the refrigeration system __________. Illustration GS-RA-01 The hose labeled "H" should be connected to the suction service valve service port, the hose labeled "J" should be connected to the vapor valve on the refrigerant cylinder and the valve labeled "G" should be open. The hose labeled "H" should be connected to the suction service valve service port, the hose labeled "J" should be connected to the vapor valve on the refrigerant cylinder and the valve labeled "G" should be closed. The hose labeled "K" should be connected to the suction service valve service port, the hose labeled "J" should be connected to the vapor valve on the refrigerant cylinder and the valve labeled "C" should be closed. The hose labeled "K" should be connected to the suction service valve service port, the hose labeled "J" should be connected to the vapor valve on the refrigerant cylinder and the valve labeled "C" should be closed. Refrigeration & Air Conditioning
D What is the primary purpose of a reach rod as used as a valve remote operator? It changes the type of motion normally required to operate the valve. It decreases the turning effort required to operate the valve. It reverses the direction of rotation normally required to operate the valve. It allows for the operation of valves that would otherwise be out of reach. Remote Control Equipment
A Where is the location of a chain-operated valve when a chain wheel is attached to the stem and is associated with an endless chain for operation? The valve is located too far directly above the deck where it is operated from. The valve is located too far directly across from the location where it is operated. The valve is located too far directly below the deck where it is operated from. A chain-operated valve can be used in any of the applications listed above. Remote Control Equipment
D In what application is a remote valve operator most likely to be located outside the machinery space when the valve itself is located within the machinery space? A valve located in a compressed air line. A valve located in potable-water transfer line. A valve located in a sea-water cooling line. A valve located in a fuel oil transfer line. Remote Control Equipment
B Suppose a remote valve operator is fitted with a gearbox. What is the purpose of the gearbox? The gearbox may be used to change the orientation of the hand wheel to the valve stem, or it may be used to reduce the turning effort, but NEVER both. The gearbox may be used to change the orientation of the hand wheel to the valve stem, or it may be used to reduce the turning effort, OR both. The gearbox is strictly used to change the orientation of the hand wheel to the valve stem. The gearbox is never used to reduce the turning effort. The gearbox is strictly used to reduce the turning effort. The gearbox is never used to change the orientation of the hand wheel to the valve stem. Remote Control Equipment
A In what application is an emergency shutdown most likely to be located outside the machinery space when the pump itself is located within the machinery space? Fuel oil transfer pump Steering pump Lube oil circulating pump Fire pump Remote Control Equipment
B What application often requires a valve to be remotely operated from a control station, where the valve itself is operated by an electric, pneumatic, or hydraulic motor? A small valve that is routinely operated during plant operations. A large valve that is routinely operated during plant operations. A large valve that is rarely operated during plant operations. A small valve that is rarely operated during plant operations. Remote Control Equipment
D What type of valve would be fitted with a quarter-turn power actuator, such as a rack-and-pinion? Non-rising stem gate valve Rising stem gate valve Globe valve Butterfly valve Remote Control Equipment
D What is the purpose of the torque limit switch as fitted on an electric motor operated rising stem gate valve? The torque limit switch protects the valve from being damaged if a foreign object prevents the valve from fully opening. The torque limit switch protects the motor from being damaged if a foreign object prevents the valve from fully opening. The torque limit switch protects the motor from being damaged if a foreign object prevents the valve from fully closing. The torque limit switch protects the valve from being damaged if a foreign object prevents the valve from fully closing. Remote Control Equipment
A Remote valve operators are frequently fitted with a handwheel for local operation if the motor fails. If this is so, what is the procedure for local manual control? First move the lever to disengage the motor clutch, and then rotate the hand wheel. Just rotate the hand wheel in the appropriate direction for valve operation. First move the lever to engage the motor clutch, and then rotate the hand wheel. Motor operated valves are generally not fitted with local hand wheels. Remote Control Equipment
D A vessel is in compliance with federal regulations regarding the discharge of sewage by __________. holding all sewage onboard treating sewage in an approved system pumping the sewage ashore to an approved container All of the above. Sanitary / Sewage Systems
C Which type of Marine Sanitation Device (MSD) is used solely for the storage of sewage and flush water at ambient air pressure and temperature? Type I Type II Type III Type IV Sanitary / Sewage Systems
C Which of the following statements correctly describes the construction of the close coupled sanitary pump shown in the illustration? Illustration GS-0070 The pump housing and motor frame provide for radial adjustment of the shaft coupling. The pump impeller is classified as double suction. The pump and motor have a common shaft. The pump suction and discharge connections are made with screwed pipe fittings. Sanitary / Sewage Systems
C Which type of Marine Sanitation Device (MSD) is used solely for the storage of sewage and flush water at ambient air pressure and temperature? Type I Type II Type III Type IV Sanitary / Sewage Systems
C A constant pressure range is maintained in the potable water system of many vessels by using __________. constant speed supply pumps variable speed supply pumps an air cushion in the hydro-pneumatic tank a pressure regulator in the pressure tank discharge piping Sanitary / Sewage Systems
A According to the illustration, which of the following conditions would most likely cause pump "A" to short cycle? Illustration GS-0173 The hydro-pneumatic expansion tank is operating with an insufficient air charge. The hydro-pneumatic tank is operating with a low water level. A low water level exists in the potable water storage tank. Pump "A" wearing rings have excessive clearance. Sanitary / Sewage Systems
B The flame screens installed on sewage system tank vents prevent explosions by __________. allowing the escape of flammable vapors dissipating the heat of a flame absorbing any flammable vapors in the vicinity preventing flammable vapors from entering the tank Sanitary / Sewage Systems
D If water continues to trickle into the toilet bowl after the device shown in the illustration has apparently closed, the problem is likely due to __________. Illustration GS-0155 "E" being stuck or held in a position other horizontal a problem with "H" that allows continuous low flow across the device "A" being cocked into a fully open position "C" having developed a warp or ripple at the seating surface Sanitary / Sewage Systems
C If water continues to flow excessively from the device shown in the illustration, the problem is most likely due to __________. Illustration GS-0155 "E" being stuck or held in a position other than indicated in the illustration a hole being formed in the outboard edge of "C" item "H" being fouled or plugged a hole developing in "B" Sanitary / Sewage Systems
D A vessel is in compliance with federal regulations regarding the discharge of sewage by __________. holding all sewage onboard treating sewage in an approved system pumping the sewage ashore to an approved container All of the above. Sanitary / Sewage Systems
A Marine sanitation devices installed on vessels must be certified by the __________. U.S. Coast Guard American Bureau of Shipping Society of Naval Architects and Marine Engineers Environmental Protection Agency Sanitary / Sewage Systems
A Coast Guard regulations concerning marine sanitation devices may be found in __________. 33 CFR Section 159 33 CFR Section 153 33 CFR Section 155 33 CFR Section 156 Sanitary / Sewage Systems
B The process of grinding, shredding, or reducing the size of sewage particles is known as __________. detention maceration bulking chlorinating Sanitary / Sewage Systems
C Which type of Marine Sanitation Device (MSD) is used solely for the storage of sewage and flush water at ambient air pressure and temperature? Type I Type II Type III Type IV Sanitary / Sewage Systems
A According to the illustration, which of the following conditions would most likely cause Pump "A" to short cycle? Illustration GS-0173 The hydro-pneumatic expansion tank is operating with an insufficient air charge. The hydro-pneumatic tank is operating with a low water level. A low water level exists in the potable water storage tank. Pump "A" wearing rings have excessive clearance. Sanitary / Sewage Systems
A A pneumatic pressure tank is installed in a sanitary system to __________. reduce excessive cycling of the sanitary pump prevent the sanitary pump from losing suction provide a higher pressure in the system than the pump can deliver increase water flow through the system Sanitary / Sewage Systems
D What type of bottom construction is used on most commercial deep-draft vessels with the exception of tankers? Triple bottom construction Single bottom construction Double hull construction Double bottom construction Ship Construction And Repairs
A What is the name of an internal passage of watertight construction fitted along the centerline between the double-bottoms of some ships, usually from the forepeak to the forward machinery space bulkhead, used to carry pipe work along the length of the ship to the various holds or tanks? Duct keel Vertical keel Bar keel Pipe keel Ship Construction And Repairs
D What statement is true concerning the keel arrangements of a double-bottomed ship? A ship with an "duct keel" has a single continuous transverse girder positioned along the centerline and perpendicular to the flat plate keel, and a ship with a "I-section keel" has two continuous transverse girders spaced apart and positioned on either side of the centerline and perpendicular to the flat plate keel. A ship with an "I-section keel" has a single continuous transverse girder positioned along the centerline and perpendicular to the flat plate keel, and a ship with a "duct keel" has two continuous transverse girders spaced apart and positioned on either side of the centerline and perpendicular to the flat plate keel. A ship with an "duct keel" has a single continuous longitudinal girder positioned along the centerline and perpendicular to the flat plate keel, and a ship with a "I-section keel" has two continuous longitudinal girders spaced apart and positioned on either side of the centerline and perpendicular to the flat plate keel. A ship with an "I-section keel" has a single continuous longitudinal girder positioned along the centerline and perpendicular to the flat plate keel, and a ship with a "duct keel" has two continuous longitudinal girders spaced apart and positioned on either side of the centerline and perpendicular to the flat plate keel. Ship Construction And Repairs
D For a transverse-framed ship of double-bottom construction, what structural members supports the inner bottom shell (or tank-tops)? Longitudinally arranged continuous vertical floors. Transversely arranged continuous vertical girders. Longitudinally arranged continuous vertical girders. Transversely arranged continuous vertical floors. Ship Construction And Repairs
C What is usually contained within the double-bottom tanks associated with the machinery spaces? Machinery space double-bottom tanks generally contain liquid cargo. Machinery space double-bottom tanks generally are kept dry and function as void spaces. Machinery space double-bottom tanks generally contain fuel oil, lubricating oil, or fresh water. Machinery space double-bottom tanks generally contain seawater ballast. Ship Construction And Repairs
B How is access to the double-bottom tanks usually provided for inspection, cleaning, maintenance, and repairs of tank interiors? Gasketed and bolted manholes associated with vertical tank boundaries Gasketed and bolted manholes associated with the inner plating (tank tops). Hinged hatches associated with the inner plating (tank tops). Gasketed and bolted manholes associated with the outer plating. Ship Construction And Repairs
D While in dry-dock, what means are provided for completely draining the double bottom tanks in preparation for inspection? Sounding tubes. Gasketed and bolted manholes. Stripping eductor connections. Docking plugs. Ship Construction And Repairs
D As it applies to a transverse-framed ship with double bottom construction, what does the term "floor" represent? Floors are vertical longitudinal members supporting the inner-bottoms. Floors are the actual inner-bottom tank tops.