Pass Benchmark: 70% (21/30) • Standard: USCG NMC / 46 CFR

USCG Refrigeration & Air Conditioning (Set 6)

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Question 1 of 30

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?

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30 MCQs

#1 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? #2 Which of the conditions listed could cause excessively low refrigerant pressure at the compressor suction of a TXV controlled refrigeration system? #3 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? #4 High suction pressure accompanied by low suction temperature to a refrigeration system compressor is caused by which of the following? #5 Low compressor head pressure in a refrigeration system can be caused by which of the following? #6 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? #7 When a refrigeration compressor motor fails to start, the FIRST thing that should be checked for is what? #8 If the refrigeration compressor crankcase is sweating or frosting and is operating with an unusual noise, what is most likely the cause? #9 If a refrigeration system were short of refrigerant, besides an elevated box temperature, what would be an observable symptom? #10 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? #11 A refrigeration unit will tend to short cycle when operating under what conditions? #12 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? #13 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? #14 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? #15 In a refrigeration system, the push-pull technique can be used for the recovery of the refrigerant in what state? #16 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? #17 What is true concerning highly contaminated refrigerant recovered from burned out small appliances? #18 Technicians servicing small refrigeration appliances can employ what type of recovery equipment? #19 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? #20 Before charging a refrigeration unit, unless quick disconnect fittings are used, the refrigerant charging hoses should be prepared in what way? #21 Concerning the charging of refrigerant into a vapor compression refrigerating system, which of the following is true? #22 How should small appliances with less than three pounds of refrigerant be charged with refrigerant? #23 Charging liquid HCFC-123 into a system under a deep vacuum could cause what to happen unless necessary precautions are taken? #24 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? #25 Which of the valves listed is normally closed when charging the refrigeration system through the high side? #26 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? #27 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? #28 With regards to shipboard refrigeration systems, after July 1, 1992, what action became illegal? #29 According to 46 CFR, Part 58, for protection purposes, what is required of all refrigeration systems? #30 What would be an example of a small appliance as defined in the EPA Clean Air Act rules?

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