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

USCG Refrigeration & Air Conditioning (Set 1)

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Question 1 of 30

Traditionally, which of the listed refrigerants has been more suitable than the others for use in a centrifugal refrigeration compressor?

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30 MCQs

#1 Traditionally, which of the listed refrigerants has been more suitable than the others for use in a centrifugal refrigeration compressor? #2 Which of the fluids listed is suitable for use as a secondary refrigerant? #3 Which of the following refrigerants is chlorine free and safe regarding atmospheric ozone depletion? #4 What is the most important consideration in selecting a lubricating oil for use in a refrigeration compressor? #5 The lubrication oil in the crankcase of a refrigeration compressor that is shut down is heated. For what purpose is this done? #6 The "tare weight" of a refrigerant storage cylinder refers to what weight? #7 The term 'oil foaming' in refrigeration practice, is used to describe what event? #8 At ambient temperature and atmospheric pressure, what is the status of R-134a? #9 What is the physical state and pressure condition of refrigerant as it leaves a receiver in a typical refrigeration system? #10 Refrigerant entering the compressor of a refrigeration system should be in which of the following conditions? #11 Before charging a refrigeration unit, unless quick disconnect fittings are used, the refrigerant charging hoses should be prepared in what way? #12 The amount of HCFC-123 in a storage cylinder is measured by what means? #13 Loss of refrigerant during the process of purging of air and non-condensable gases can be kept to a minimum by what action? #14 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? #15 In a low-pressure centrifugal chiller, what is meant by the term 'high efficiency purge unit?' #16 Which of the valves listed is normally closed when charging the refrigeration system through the high side? #17 In reclaiming recovered refrigerant, which type of contamination will the reclamation process be unable to separate? #18 In a refrigeration system, the push-pull technique can be used for the recovery of the refrigerant in what state? #19 What is true concerning highly contaminated refrigerant recovered from burned out small appliances? #20 Technicians servicing small refrigeration appliances can employ what type of recovery equipment? #21 What is true concerning frost build-up on the evaporator coils of a multi-box direct expansion refrigeration system? #22 If the combination moisture indicator and sight glass indicates an accumulation of moisture within the system, which of the listed procedures would be the most practical to follow? #23 In addition to the drive belt itself, a V-belt that is tensioned too tight will cause excessive wear to what other drive component? #24 When one belt of a multiple V-belt drive requires replacing, what will be required? #25 Excessively tight drive belts installed between a motor and a refrigeration compressor pulley may cause what condition? #26 When installing a mechanical shaft seal on a refrigeration compressor, extreme care must be taken to prevent what from happening? #27 If the discharge reed valves used in a refrigeration compressor are leaking badly, what statement is true? #28 When replacing a thermostatic expansion valve power element, what is true concerning the thermal bulb? #29 If the evaporator coil horizontal return line of a container refrigeration system is less than 0.875" (2.21 cm) in diameter (considered small); the thermostatic expansion valve sensing bulb should be attached where on the return line? #30 Concerning the operation of refrigeration systems, frosting or sweating of a liquid line is usually indicative of what condition?

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