Pass Benchmark: 70% (21/30) • Standard: USCG NMC / 46 CFR
USCG Refrigeration & Air Conditioning (Set 16)
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Question 1 of 30
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?
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30 MCQs #1 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? #2 What must be done to use standard leak detection methods on a low-pressure refrigeration system charged with refrigerant? #3 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 fluorocarbon refrigerants to the atmosphere? #4 What is the correct color-coding of refrigerant recovery cylinders regardless of the refrigerant contained within? #5 What is the color-coding for a storage container of R-134a refrigerant? #6 Which of the lettered components shown in the illustration indicates the high-pressure cutout? Illustration GS-RA-12
Illustration GS-RA-12: the U.S. Coast Guard has not released this illustration. #7 When the relief valve opens on a refrigeration compressor discharge line, it discharges high-pressure refrigerant vapor to what location? #8 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
Illustration GS-RA-69: the U.S. Coast Guard has not released this illustration. #9 In the multi-evaporator refrigeration system shown in the illustration, what is the proper name for the valve labeled "29"? Illustration GS-RA-12
Illustration GS-RA-12: the U.S. Coast Guard has not released this illustration. #10 Through which of the components shown in the illustration is flash gas formation a normal occurrence? Illustration GS-RA-25
Illustration GS-RA-25: the U.S. Coast Guard has not released this illustration. #11 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
Illustration GS-RA-51: the U.S. Coast Guard has not released this illustration. #12 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 #13 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
Illustration GS-RA-48: the U.S. Coast Guard has not released this illustration. #14 In the presence of an open flame or hot surfaces, chlorinated fluorocarbon refrigerants decompose and form what chemical substance? #15 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? #16 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
Illustration GS-RA-13: the U.S. Coast Guard has not released this illustration. #17 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
Illustration GS-RA-13: the U.S. Coast Guard has not released this illustration. #18 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? #19 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? #20 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
Illustration GS-RA-32: the U.S. Coast Guard has not released this illustration. #21 Regarding heat transfer principles, which of the following are true? #22 In a low-pressure refrigeration system, excessive running of the purge recovery unit generally indicates which probable condition? #23 Heat is removed from the refrigerant circulating through the refrigeration system, shown in the illustration, by which component? Illustration GS-RA-12
Illustration GS-RA-12: the U.S. Coast Guard has not released this illustration. #24 When the relief valve opens on a refrigeration compressor discharge line, it discharges high-pressure refrigerant vapor to what location? #25 Which of the lettered components shown in the illustration indicates the high-pressure cutout? Illustration GS-RA-12
Illustration GS-RA-12: the U.S. Coast Guard has not released this illustration. #26 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? #27 Heat is removed from the refrigerant circulating through the refrigeration system, shown in the illustration, by which component? Illustration GS-RA-12
Illustration GS-RA-12: the U.S. Coast Guard has not released this illustration. #28 Sea water or low temperature central fresh water is typically provided to a ship's stores refrigeration plant for what purpose? #29 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
Illustration GS-RA-07: the U.S. Coast Guard has not released this illustration. #30 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
Illustration GS-RA-07: the U.S. Coast Guard has not released this illustration.
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