Pass Benchmark: 70% • Standard: USCG NMC / 46 CFR
USCG Engine Refrigeration (Supplementary) (Set 5)
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Question 1 of 30
Which of the following illustrated thermal expansion valves would be appropriate to use on an evaporator coil with a 2 psi pressure drop, where externally adjustable superheat and a replaceable power element are both desired? GS-RA-06
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30 MCQs #1 Which of the following illustrated thermal expansion valves would be appropriate to use on an evaporator coil with a 2 psi pressure drop, where externally adjustable superheat and a replaceable power element are both desired? GS-RA-06 #2 When a refrigeration compressor is in the 'off' cycle, the thermal expansion valve will react in what way? #3 Of the various possible methods shown in the illustration, which is the correct method of attaching a TXV feeler bulb to a small large line (7/8" and larger) with a horizontal run? GS-RA-50
Illustration GS-RA-50: the U.S. Coast Guard has not released this illustration. #4 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? #5 Which of the listed statements describes the method used to determine the amount of superheat present in the suction gas leaving the evaporator coil? GS-RA-16 #6 Which of the following conditions will occur if the power element of the thermostatic expansion valve shown in the illustration loses its charge? GS-RA-07
Illustration GS-RA-07: the U.S. Coast Guard has not released this illustration. #7 If the needle and seat assembly is excessively eroded, the valve cage assembly can be replaced. In replacing the original valve cage assembly rated at 1/2 tons, what would be the result if the replacement valve cage was oversized at 5 tons? GS-RA-07
Illustration GS-RA-07: the U.S. Coast Guard has not released this illustration. #8 Concerning frost appearing on one set of evaporator coils of a multi-box, direct expansion type refrigeration system, what is true? #9 The pressure in the part of a high pressure refrigeration system about to be opened for a non-major repair should be brought to what value? #10 Overfilling a refrigerant container is extremely dangerous because of the high pressures generated. The generation of pressure is the result of what? #11 You are checking the supply chilled water temperature thermistor probe on a high- pressure hermetic centrifugal chiller. Using the illustrated chart, what statement is true if the supply water temperature is verified 45 ° F with a digital thermometer. GS-RA-48
Illustration GS-RA-48: the U.S. Coast Guard has not released this illustration. #12 A high-pressure centrifugal chiller currently charged with R-134a is being evaluated for the need for leak testing. Using the leak-test procedures decision tree illustrated and the R-134a pressure-temperature chart illustrated, with the machine idle and the pressures equalized at 10 psig with an ambient temperature of 60 ° F, what statement is true? GS-RA-47
Illustration GS-RA-47: the U.S. Coast Guard has not released this illustration. #13 If you find a refrigerant leak while using a halide torch, what will happen to the flame as the exploring tube approaches the leak? #14 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. #15 An air-cooled refrigerated container unit using R-134a as a refrigerant has a box temperature set point of -15 °F, but it is currently operating with a stable return air temperature of 0 °F. The fresh air makeup vent is closed, the unit is operating at 460 VAC/60 Hz, and the unit is in full capacity cool (modulating valve 100% open). Using the illustrated troubleshooting guide, what would be the normal range of expected discharge pressures if the ambient air temperature is 90 °F? GS-RA-52
Illustration GS-RA-52: the U.S. Coast Guard has not released this illustration. #16 If the running suction pressure at the refrigeration compressor of a TXV controlled air- cooled refrigeration system is below normal, which of the following can be a cause? #17 If a refrigeration compressor were short cycling on the low pressure cutout switch, what is the most probable cause? #18 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? #19 What is the correct color coding of refrigerant recovery cylinders regardless of the refrigerant contained within? #20 As shown in figure "B" of the illustrated self-contained recovery unit connection diagrams, what is the recovery method supported by the connection scheme? GS-RA-33
Illustration GS-RA-33: the U.S. Coast Guard has not released this illustration. #21 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? #22 The most cost-effective method of recovering refrigerant from a low pressure chiller with more than 500 lbs of refrigerant and to meet EPA requirements is to recover the refrigerant using what protocol? #23 Why is a purge recovery unit typically fitted on low pressure centrifugal chillers? #24 As shown in the illustrated flow diagram for a self-contained recovery unit designed for the recovery of refrigerants from high pressure appliances as defined by the EPA Clean Air Act rules, what is the functional purpose of the item labeled "FS2"? GS-RA-32
Illustration GS-RA-32: the U.S. Coast Guard has not released this illustration. #25 The amount of HCFC-123 in a storage cylinder is measured by what means? #26 Which of the illustrated devices would be the LEAST accurate for the purposes of weighing-in a refrigerant charge? GS-RA-45 #27 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. #28 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 #29 Refillable tanks used to ship CFC and HCFC refrigerants or used to recover these refrigerants must meet the standards of what entity? #30 Which best defines a "Type I" small refrigeration appliance according to the EPA Regulations Section 608?
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