Pass Benchmark: 70% • Standard: USCG NMC / 46 CFR
USCG Engine Refrigeration (Supplementary) (Set 1)
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Question 1 of 30
Which of the following substances is normally classified as a low pressure refrigerant?
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30 MCQs #1 Which of the following substances is normally classified as a low pressure refrigerant? #2 R-134a is often the replacement for which older type of refrigerant? #3 What is the color coding for a storage container of R-134a refrigerant? #4 If you mistakenly change from a lower pour point lubricant to a higher pour point lubricant in a refrigeration system, what will be the result? #5 Properties of a good refrigeration compressor lubricating oil include which of the following? #6 The gas that exists in the stratosphere forming a protective shield that helps to protect the environment from the harmful effects ultraviolet radiation is called what? #7 Regarding heat transfer principles, which of the following is true? #8 What is the physical state and pressure condition of refrigerant as it enters the condenser of a typical refrigeration system. #9 What is the pressure and condition of the refrigerant entering the receiver of a refrigeration system? #10 When repairing a refrigeration system, a swaging tool set would be used to carry out which of the following operations? #11 Which of the following statements is true concerning the illustrated gauge manifold set? Illustration GS-RA-01 #12 Which pair of the illustrated service gauge manifold sets would require switching hoses when transitioning from a dehydration evacuation to refrigerant charging? Illustration GS-RA-30 #13 With a service gauge manifold set connected to a refrigerant compressor as shown in the illustration, which arrangement of the gauge manifold set valves and compressor Service Valves would allow for simultaneous reading of the compressor suction and discharge pressures? GS-RA-03
Illustration GS-RA-03: the U.S. Coast Guard has not released this illustration. #14 In a refrigeration system, once the gage manifold hoses are attached to the compressor service valve connections and properly purged, what should be the status of the manifold valves and the service valves when the purpose for attachment is to read system pressures? #15 When purging a refrigeration gage manifold using system pressure as the source of refrigerant for purging, which of the fittings listed is normally tightened LAST? #16 In a refrigeration system, from what location would air and non-condensable gases be removed? #17 Concerning the charging of refrigerant into a vapor compression refrigerating system, which of the following is true? #18 How should small appliances with less than three pounds of refrigerant be charged with refrigerant? #19 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? GS-RA-69
Illustration GS-RA-69: the U.S. Coast Guard has not released this illustration. #20 During normal operation, traditionally, how has most of the refrigerant released to the atmosphere from low pressure systems? #21 Charging liquid HCFC-123 into a system under a deep vacuum could cause what to happen unless necessary precautions are taken? #22 In a low pressure refrigeration system, excessive running of the purge recovery unit generally indicates which probable condition? #23 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? #24 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 refrigeration system. GS-RA-01 #25 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? GS-RA-51
Illustration GS-RA-51: the U.S. Coast Guard has not released this illustration. #26 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 fluoro-carbon refrigerants to the atmosphere? #27 The process of removing refrigerant from a system and storing it without testing or processing it in any way is known as what under the EPA Clean Air Act rule definitions? #28 What is the correct color coding of refrigerant recovery cylinders regardless of the refrigerant contained within? #29 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? #30 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?
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