Pass Benchmark: 70% (21/30) • Standard: USCG NMC / 46 CFR
USCG Refrigeration & Air Conditioning (Set 12)
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Question 1 of 30
What type of HVAC system is characterized by poor air distribution and ventilation and low system heat loads?
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30 MCQs #1 What type of HVAC system is characterized by poor air distribution and ventilation and low system heat loads? #2 What type of HVAC system is characterized by a having a split supply air stream, with one for cold air and the other for hot air? #3 What type of HVAC system is characterized by having control dampers in locations other than the outside air supply, outside air exhaust, and recirculation damper applications? #4 What type of pump is invariably used as a circulator in a hydronic heating system? #5 What statement is true concerning a one-pipe hydronic heating system? #6 It is absolutely essential that hydronic heating system hot water piping be kept free of air. Assuming that a system is initially properly filled with water, what is the primary source of air contamination? #7 Concerning cargo-hold dehumidification, what statement is true? #8 What statement is true concerning a liquid desiccant cargo-hold dehumidification system? #9 What statement is true concerning a liquid desiccant cargo-hold dehumidification system? #10 With regard to the cooling and heating coils and humidification and regeneration chambers of a liquid cargo-hold dehumidification system, what statement is true? #11 To prevent damage to dry cargoes, the cargo hold ventilation and dehumidification systems play a key role. In terms of the maintained dew point, what statement is true? #12 To determine the average cargo hold dew point temperature, at what location would the dew point be measured? #13 What temperature associated with the psychrometric properties of air is measured by an ordinary thermometer? #14 Which of the hand valve configurations for the gauge manifold set is the correct set up for monitoring both the low and high system pressures? Illustration GS-RA-03
Illustration GS-RA-03: the U.S. Coast Guard has not released this illustration. #15 Which of the following leak detectors would be appropriate for use in leak detecting on a system currently pressurized with nitrogen? Illustration GS-RA-04 #16 Some chlorinated fluorocarbon refrigerants may decompose into a toxic irritating gas under what conditions? #17 If you find a refrigerant leak while using a halide torch, what will happen to the flame as the exploring tube approaches the leak? #18 Moisture is removed from recovered refrigerant using a recycling machine by what means? #19 As shown in figure "B" of the illustrated self-contained recovery unit connection diagrams, what is the recovery method supported by the connection scheme? Illustration GS-RA-33
Illustration GS-RA-33: the U.S. Coast Guard has not released this illustration. #20 When removing the primary refrigerant from a system using water as a secondary refrigerant, it is important to follow which procedure(s) to safeguard the equipment? #21 A "hygroscopic" lubricant used in refrigeration compressors would have what characteristic? #22 When checking the oil level in a refrigeration compressor, under what conditions would the most accurate reading be obtained? #23 Which of the illustrated gauges is capable of measuring vacuums at the micron level for the purpose of proving system dehydration during system evacuation with a vacuum pump, but displays the achieved vacuums at incremental threshold intervals rather than continuously? Illustration GS-RA-37 #24 The coil temperature measured at the expansion valve sensing bulb of an operating system is 10°F. The low side pressure with the compressor running as shown on the gauge illustrated indicates 15 psig. What adjustments or changes, if any, should be made to the system? Illustration GS-RA-16 #25 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? Illustration GS-RA-07
Illustration GS-RA-07: the U.S. Coast Guard has not released this illustration. #26 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? Illustration GS-RA-06 #27 Which of the statements listed is applicable to the thermostatic expansion valve shown in the illustration? Illustration GS-RA-07
Illustration GS-RA-07: the U.S. Coast Guard has not released this illustration. #28 What is one function of the thermal expansion valve used in a refrigeration system? #29 A thermal expansion valve installed in a refrigeration system is controlled by the action of what device? #30 When the sensing bulb of a thermostatic expansion valve is charged with a fluid different from the charge used in the system, what name of the charge is associated with the power element?
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