Refrigeration-Air Conditioning
1. When repairing a refrigeration system, a swaging tool set would be used to carry out which of the
following operations? - ANSWER-Swaging tools can be used to expand an end of one tube to fit onto
a tube of the same original outside diameter.
2. 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? - ANSWER-the compressor will shut
down by the action of the high-pressure cutout switch
3. When the relief valve opens on a refrigeration compressor discharge line, it discharges high-
pressure refrigerant vapor to what location? - ANSWER-suction side of the compressor
4. Which of the lettered components shown in the illustration indicates the high-pressure cutout?
Illustration GS-RA-12 - ANSWER-X
5. The rupture disc on a low-pressure centrifugal refrigeration unit is used as an overpressure
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? - ANSWER-on top of chiller evaporator shell
6. 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? - ANSWER-Crankcase pressure regulator
7. A reheater in an air conditioning system performs what function? - ANSWER-restores the
conditioned air temperature to a comfortable level
8. What is one benefit of maintenance of proper air circulation in an air conditioned cargo space? -
ANSWER-reduced slime and mold
9. In a two stage centrifugal air conditioning system, the liquid refrigerant passes through the
condenser directly to what component? - ANSWER-economizer
10. In an air conditioning system, what is the name of the chamber where the duct-work originates? -
ANSWER-plenum chamber
11. 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 - ANSWER-80 degrees F
,Refrigeration-Air Conditioning
12. In general, the thermal bulb for a thermal expansion valve used in a reciprocating air conditioning
system is usually charged with what substance? - ANSWER-the same refrigerant as the system
13. Heat is removed from the refrigerant circulating through the refrigeration system, shown in the
illustration, by which component? Illustration GS-RA-12 - ANSWER-B
14. Sea water or low temperature central fresh water is typically provided to a ship's stores
refrigeration plant for what purpose? - ANSWER-condense the refrigerant gas
15. Zinc plates commonly found in refrigeration systems and used as sacrificial anodes are located
where? - ANSWER-salt water side of the condenser
16. 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? - ANSWER-TXV hunting
17. Moisture entering a typical refrigeration system will most likely produce what effect? - ANSWER-
freeze in the expansion valve
18. A small obstruction at the thermostatic expansion valve inlet will result in which of the following
conditions? - ANSWER-Lower than normal suction pressure.
19. An obstructed expansion valve may be indicated by an incompletely cooled evaporator and what
other symptom? - ANSWER-frosting at the evaporator inlet
20. 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 - ANSWER-The valve will fail
closed, providing no cooling capacity.
21. 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 - ANSWER-The expansion
valve would hunt excessively, alternately starving and overfeeding the evaporator coil.
, Refrigeration-Air Conditioning
22. If the superheat value of the thermostatic expansion valve is adjusted too high, what would be
the result? - ANSWER-the suction line of the compressor will be abnormally warm
23. 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? - ANSWER-the suction line will be
abnormally cold and liquid may flood back to the compressor
24. 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 - ANSWER-D
25. How should small appliances with less than three pounds of refrigerant be charged with
refrigerant? - ANSWER-vapor charged
26. Before charging a refrigeration unit, unless quick disconnect fittings are used, the refrigerant
charging hoses should be prepared in what way? - ANSWER-they should be purged with refrigerant
27. Which of the illustrated devices would be the LEAST accurate for the purposes of weighing-in a
refrigerant charge? Illustration GS-RA-45 - ANSWER-C
28. Concerning the charging of refrigerant into a vapor compression refrigerating system, which of
the following is true? - ANSWER-when charging as a liquid it should be to the high side only
29. 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 - ANSWER-C
30. 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? - ANSWER-$25,000
31. 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? -
ANSWER-before performing maintenance, service or repair that could reasonably be expected to
release Class 1 or Class 2 refrigerants into the atmosphere
1. When repairing a refrigeration system, a swaging tool set would be used to carry out which of the
following operations? - ANSWER-Swaging tools can be used to expand an end of one tube to fit onto
a tube of the same original outside diameter.
2. 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? - ANSWER-the compressor will shut
down by the action of the high-pressure cutout switch
3. When the relief valve opens on a refrigeration compressor discharge line, it discharges high-
pressure refrigerant vapor to what location? - ANSWER-suction side of the compressor
4. Which of the lettered components shown in the illustration indicates the high-pressure cutout?
Illustration GS-RA-12 - ANSWER-X
5. The rupture disc on a low-pressure centrifugal refrigeration unit is used as an overpressure
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? - ANSWER-on top of chiller evaporator shell
6. 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? - ANSWER-Crankcase pressure regulator
7. A reheater in an air conditioning system performs what function? - ANSWER-restores the
conditioned air temperature to a comfortable level
8. What is one benefit of maintenance of proper air circulation in an air conditioned cargo space? -
ANSWER-reduced slime and mold
9. In a two stage centrifugal air conditioning system, the liquid refrigerant passes through the
condenser directly to what component? - ANSWER-economizer
10. In an air conditioning system, what is the name of the chamber where the duct-work originates? -
ANSWER-plenum chamber
11. 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 - ANSWER-80 degrees F
,Refrigeration-Air Conditioning
12. In general, the thermal bulb for a thermal expansion valve used in a reciprocating air conditioning
system is usually charged with what substance? - ANSWER-the same refrigerant as the system
13. Heat is removed from the refrigerant circulating through the refrigeration system, shown in the
illustration, by which component? Illustration GS-RA-12 - ANSWER-B
14. Sea water or low temperature central fresh water is typically provided to a ship's stores
refrigeration plant for what purpose? - ANSWER-condense the refrigerant gas
15. Zinc plates commonly found in refrigeration systems and used as sacrificial anodes are located
where? - ANSWER-salt water side of the condenser
16. 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? - ANSWER-TXV hunting
17. Moisture entering a typical refrigeration system will most likely produce what effect? - ANSWER-
freeze in the expansion valve
18. A small obstruction at the thermostatic expansion valve inlet will result in which of the following
conditions? - ANSWER-Lower than normal suction pressure.
19. An obstructed expansion valve may be indicated by an incompletely cooled evaporator and what
other symptom? - ANSWER-frosting at the evaporator inlet
20. 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 - ANSWER-The valve will fail
closed, providing no cooling capacity.
21. 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 - ANSWER-The expansion
valve would hunt excessively, alternately starving and overfeeding the evaporator coil.
, Refrigeration-Air Conditioning
22. If the superheat value of the thermostatic expansion valve is adjusted too high, what would be
the result? - ANSWER-the suction line of the compressor will be abnormally warm
23. 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? - ANSWER-the suction line will be
abnormally cold and liquid may flood back to the compressor
24. 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 - ANSWER-D
25. How should small appliances with less than three pounds of refrigerant be charged with
refrigerant? - ANSWER-vapor charged
26. Before charging a refrigeration unit, unless quick disconnect fittings are used, the refrigerant
charging hoses should be prepared in what way? - ANSWER-they should be purged with refrigerant
27. Which of the illustrated devices would be the LEAST accurate for the purposes of weighing-in a
refrigerant charge? Illustration GS-RA-45 - ANSWER-C
28. Concerning the charging of refrigerant into a vapor compression refrigerating system, which of
the following is true? - ANSWER-when charging as a liquid it should be to the high side only
29. 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 - ANSWER-C
30. 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? - ANSWER-$25,000
31. 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? -
ANSWER-before performing maintenance, service or repair that could reasonably be expected to
release Class 1 or Class 2 refrigerants into the atmosphere
