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Engine · 134 questions

Retired questions · Refrigeration AC - USCG Exam Questions

These are retired questions the Coast Guard no longer draws exams from. They stay online for reference; the current questions are in Refrigeration AC.

Refrigeration cycles and components, compressors, refrigerants, and marine air conditioning systems.

Every question below is a real U.S. Coast Guard exam question with four choices. Answer one and the correct choice is revealed instantly, with the USCG reference and illustration where the question uses one.

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All Retired questions · Refrigeration AC questions

Questions 101–134 of 134 · page 2 of 2

  1. #441 Which lettered component, shown in the illustration, indicates the location of the receiver? GS-RA-12 illustration
  2. #443 As shown in the illustrated LP centrifugal chiller pressure maintenance system, what is its functional purpose? GS-RA-40 illustration
  3. #444 What is the purpose of the pressure transducer as shown in the illustration? GS-RA-17 illustration
  4. #448 If the valve labeled "D" in the illustration is a suction service valve, what will the port labeled "7" be connected to? GS-RA-08 illustration
  5. #453 Seawater or low temperature central fresh water is typically provided to a ship's stores refrigeration plant for what purpose?
  6. #454 Heat is removed from the refrigerant circulating through the refrigeration system, shown in the illustration, by which component? GS-RA-12 illustration
  7. #458 Through which of the components shown in the illustration is flash gas formation a normal occurrence? GS-RA-25 illustration
  8. #459 In the multi-evaporator refrigeration system shown in the illustration, what is the proper name for the valve labeled "29"? GS-RA-12 illustration
  9. #463 Which of the following illustrated expansion valves is designed to maintain a constant evaporator pressure rather than a constant evaporator superheat... illustration
  10. #464 Which of the following illustrated thermal expansion valves would be appropriate to use on an evaporator coil with a 2 psi pressure drop, where extern... illustration
  11. #470 Which of the statements listed is applicable to the thermostatic expansion valve shown in the illustration? GS-RA-07 illustration
  12. #484 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
  13. #488 The coil temperature measured at the expansion valve sensing bulb of an operating system is 10°F. The low side pressure with the compressor running as... illustration
  14. #490 Which of the following conditions will occur if the power element of the thermostatic expansion valve shown in the illustration loses its charge? GS-R... illustration
  15. #495 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... illustration
  16. #499 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... illustration
  17. #529 As shown in the illustrated flow diagram for a self-contained recovery unit designed for the recovery of refrigerants from high pressure appliances as... illustration
  18. #534 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 refrig... illustration
  19. #538 In the presence of an open flame or hot surfaces, chlorinated fluorocarbon refrigerants decomposes and form what chemical substance?
  20. #563 When recovering the remaining R-134a refrigerant from the centrifugal chiller shown in the illustration as a vapor using the recovery unit's compresso... illustration
  21. #565 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 vacu... illustration
  22. #585 Referring to illustrated diagram, what type of HVAC system is shown? GS-RA-09 illustration
  23. #586 Referring to illustrated diagram, what type of HVAC system is shown? GS-RA-42 illustration
  24. #587 Referring to illustrated diagram, what type of HVAC system is shown? GS-RA-43 illustration
  25. #590 In the illustrated single zone HVAC system, what prevents the simultaneous flow of steam through the preheat coil and flow of chilled water through th... illustration
  26. #591 In the illustrated single zone HVAC system, what statement represents the relationship between the exhaust, outside air and recirculation dampers? Ref... illustration
  27. #592 In the illustrated terminal reheat multiple zone system, what statement represents the functioning of the summer outside air duct thermostat? GS-RA-42 illustration
  28. #593 Referring to the illustrated dual duct multiple zone HVAC system, how is the space temperature directly controlled? GS-RA-43 illustration
  29. #594 Expansion tanks when used in a ship's low temperature hot water heating system may be of the open or closed type. Referring to the illustrated central... illustration
  30. #598 What advantage does a 4-pipe hydronic heating/cooling heating system have over a 2-pipe hydronic heating/cooling system?
  31. #607 Referring to the illustrated psychrometric chart, if the dry bulb temperature is 70F and the relative humidity is 40%, what is the absolute humidity?... illustration
  32. #608 Referring to the illustrated psychrometric chart, suppose air at a dry-bulb temperature of 60F and a relative humidity of 52% passes over a heating co... illustration
  33. #609 Referring the illustrated psychrometric chart, suppose during the cooling season that air passes over a cooling coil with a mean surface temperature a... illustration
  34. #610 Referring to the illustrated psychrometric chart, under what conditions are the dry- bulb, wet-bulb, and dew point temperatures for air all equal in v... illustration

Refrigeration AC questions: what to expect

Q How many Refrigeration AC questions are in the Engine pool?

This retired set holds 134 Refrigeration AC questions the Coast Guard no longer draws on exams. They stay online for reference; the current Refrigeration AC module is the one to study.

Q What score do I need to pass the Refrigeration AC module?

Most USCG exam modules, including Refrigeration AC, require 70 percent to pass. Rules of the Road modules require 90 percent.

Q Are these the real USCG Refrigeration AC exam questions?

Yes. They are the published U.S. Coast Guard questions, matched to the National Maritime Center's 2026 sample examinations. Answer any question to see the correct choice, the USCG reference and the illustration where the question uses one.

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About the Engine question pool

The Engine pool holds the current U.S. Coast Guard questions for engineering credentials, from QMED ratings through DDE and Assistant Engineer up to Chief. Answer any question to see the correct choice instantly.