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

USCG Refrigeration & Air Conditioning (Set 5)

30:00

|

Question 1 of 30

Question Navigator

Correct Incorrect Pending Starred

Question 1 of 30

Constant superheat is maintained at the evaporator coil outlet of a refrigeration system or unit by the action of what device?

Browse Questions in Set 5

30 MCQs

#1 Constant superheat is maintained at the evaporator coil outlet of a refrigeration system or unit by the action of what device? #2 Besides the evaporator pressure, the thermal expansion valve reacts directly to changes in what parameter? #3 What is one function of the thermal expansion valve used in a refrigeration system? #4 In a refrigeration system, the pressure within the power element of a thermostatic expansion valve depends directly upon what factor? #5 A thermostatic expansion valve is properly controlling evaporator superheat. Adjusting this valve to lower the evaporator superheat setting will result in which of the following? #6 When replacing a thermostatic expansion valve power element, what is true concerning the thermal bulb? #7 Expansion valve maintenance should include which of the following procedures? #8 Which statement about calibrating a newly installed thermostatic expansion valve is correct? #9 Which of the installation steps listed is necessary for the proper operation of the thermostatic expansion valve? #10 What maintenance may be carried out on a thermostatic expansion valve? #11 When a thermostatic expansion valve is installed in a refrigerated container unit, the sensing bulb almost always requires insulation. Why is this so? #12 If the superheat setting of a thermostatic expansion valve is set too low, what would be the result, assuming that the system has a single evaporator? #13 If the superheat value of the thermostatic expansion valve is adjusted too high, what would be the result? #14 A small obstruction at the thermostatic expansion valve inlet will result in which of the following conditions? #15 An obstructed expansion valve may be indicated by an incompletely cooled evaporator and what other symptom? #16 Vapor bubbles present in the liquid upon arrival to the thermal expansion valve in a refrigeration system may cause erosion of the expansion valve's needle and seat. This, in turn, could cause what condition? #17 Moisture entering a typical refrigeration system will most likely produce what effect? #18 What is true concerning frost build-up on the evaporator coils of a multi-box direct expansion refrigeration system? #19 Some 'hot gas' defrost systems reheat the refrigerant just prior to its returning to the compressor for what purpose? #20 The FIRST thing to do to ensure that a refrigeration unit will not start while undergoing repairs is to do what? #21 Which of the precautions listed should be taken before opening any part of a refrigeration system for the purpose of accomplishing non-major repairs? #22 What is the maximum volume to which refillable refrigeration cylinders should be filled? #23 When a refrigeration compressor has developed a high head pressure as a result of a refrigerant overcharge, what should be done to compensate for or to correct this situation? #24 A box solenoid valve used in a refrigeration system should be installed in what manner? #25 When using nitrogen to pressure leak test a system, the nitrogen cylinder should always be equipped with what device or feature? #26 Which of the following statements is correct concerning the testing of an R-22 refrigeration system for leaks in an enclosed compartment with a halide torch? #27 In a refrigeration system, from what location would air and non-condensable gases be removed? #28 Loss of refrigerant during the process of purging of air and non-condensable gases can be kept to a minimum by what action? #29 In a low-pressure centrifugal chiller, what is meant by the term 'high efficiency purge unit?' #30 Concerning the operation of refrigeration systems, frosting or sweating of a liquid line is usually indicative of what condition?

Question Discussion & Notes

0

Have a doubt, memory trick, or exam update? Share your insights with fellow mariners.

Loading mariner discussions...