Pass Benchmark: 70% (21/30) • Standard: USCG NMC / 46 CFR
USCG Refrigeration & Air Conditioning (Set 11)
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Question 1 of 30
If the refrigeration compressor crankcase is sweating or frosting and is operating with an unusual noise, what is most likely the cause?
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30 MCQs #1 If the refrigeration compressor crankcase is sweating or frosting and is operating with an unusual noise, what is most likely the cause? #2 If a refrigeration system were short of refrigerant, besides an elevated box temperature, what would be an observable symptom? #3 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? #4 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? #5 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? #6 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? #7 Moisture in a refrigeration system can cause which of the following conditions? #8 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? #9 In a low pressure refrigeration system, excessive running of the purge recovery unit generally indicates which probable condition? #10 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? #11 What is true concerning highly contaminated refrigerant recovered from burned out small appliances? #12 Technicians servicing small refrigeration appliances can employ what type of recovery equipment? #13 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? #14 Why is a purge recovery unit typically fitted on low pressure centrifugal chillers? #15 How should small appliances with less than three pounds of refrigerant be charged with refrigerant? #16 Charging liquid HCFC-123 into a system under a deep vacuum could cause what to happen unless necessary precautions are taken? #17 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? #18 Which of the valves listed is normally closed when charging the refrigeration system through the high side? #19 For safe storage, the maximum allowable temperature to which refrigerant bottles should be exposed is what temperature? #20 Overfilling a refrigerant container is extremely dangerous because of the high pressures generated. The generation of pressure is the result of what? #21 Why can CFC or HCFC refrigerants leaking into a confined space or in limited surroundings cause suffocation? #22 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? #23 When starting a reciprocating refrigeration compressor that has been shut down for a period of time, you should manually throttle which valve? #24 In general, the thermal bulb for a thermal expansion valve used in a reciprocating air conditioning system is usually charged with what substance? #25 Which of the following is true concerning the class "D" air conditioning system shown in the following illustration? Illustration GS-RA-42
Illustration GS-RA-42: the U.S. Coast Guard has not released this illustration. #26 Concerning the arrangement of equipment and associated hoses shown in the illustration, which statement is true? Illustration GS-RA-59
Illustration GS-RA-59: the U.S. Coast Guard has not released this illustration. #27 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? #28 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? #29 Concerning the arrangement of equipment and associated hoses shown in the illustration, which statement is true? Illustration GS-RA-58
Illustration GS-RA-58: the U.S. Coast Guard has not released this illustration. #30 What type of HVAC system is ideally designed to serve a large public space?
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