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

USCG Refrigeration & Air Conditioning (Set 4)

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Question 1 of 30

In a refrigeration system, silica gel is found in what component?

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30 MCQs

#1 In a refrigeration system, silica gel is found in what component? #2 Standard filter/driers used in many commercial type refrigeration units may contain what type of substance? #3 Which of the devices listed will indicate whether or not a refrigeration system's dehydrator continues to be capable of removing moisture from the circulating refrigerant? #4 Moisture is removed from a refrigeration system by what action? #5 For most multi-box refrigeration systems, the refrigerant sight glass would be located where in the system? #6 A liquid indicator sight glass is useful in determining whether or not a refrigeration system is sufficiently charged. Where is it generally located in the system? #7 The primary purpose of the liquid line strainer used in a refrigeration system is to prevent dirt and scale from entering what system component(s)? #8 Capacity control of a centrifugal refrigeration compressor can be accomplished by what means? #9 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? #10 A refrigeration compressor used in a multi-box refrigeration system is designed with six of its eight cylinders able to be controlled for variable load conditions. If all of the reefer boxes are currently feeding, what percentage of the total number of compressor cylinders will be loaded after start up? #11 On a modern refrigerated container unit employing suction modulation for the purposes of capacity control and capacity limitation, what happens when the applied voltage and current draw associated with the normally open (NO) suction modulation valve located in the suction line both increase? #12 To prevent motor overload during start-up of a hermetically sealed centrifugal refrigeration system, what is true concerning the compressor suction gas variable inlet guide vanes? #13 In a multi-evaporator refrigeration system, a solenoid valve is installed in the liquid line prior to what device? #14 A liquid line solenoid valve controls refrigerant flow to the evaporator by what means? #15 How does a refrigeration solenoid valve differ from a modulating valve? #16 In a refrigeration system featuring low-side pump down prior to the automatic shut down of the compressor, the temperature of the refrigerated space is controlled by the action of a thermostat wired to what device? #17 The thermostat controlling the operation of the solenoid valve to a refrigerated box evaporator senses what temperature? #18 An arrow stamped on the valve body of a water regulating valve indicates which of the following? #19 The receiver used in a refrigeration system performs what essential function? #20 In a refrigeration plant, what is one vital purpose of the receiver? #21 In addition to pressure, most compound and standard pressure gauges used for refrigeration service are also provided with a scale indicating what parameter? #22 Hard drawn copper tubing is commonly used in larger refrigeration systems. What statement concerning its use is true? #23 In a large refrigeration system having more than one evaporator, a king solenoid valve should be installed in what location? #24 During the initial cooling down of a box temperature in a refrigeration system, which of the devices listed is used to prevent excessive gas pressure at the compressor suction for the purpose of prevention of overloading of the compressor driver? #25 In a refrigeration system that is not protected by a water failure switch, if the cooling water to the condenser fails, what will be the result for protective purposes? #26 In a refrigeration system, what component is installed directly downstream of the thermal expansion valve? #27 Refrigeration systems using forced air circulation evaporators have a tendency to cause rapid dehydration of produce in chill boxes. Which of the following will minimize this dehydration? #28 In a dry-type direct expansion refrigeration evaporator, what is true concerning the evaporator coils? #29 If a condenser coil of an air-cooled container refrigeration system becomes dirty and requires cleaning, what would be an acceptable method of cleaning? #30 What is true concerning the accumulation of air and other non-condensable gases in a refrigeration system?

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