Question 99Refrigeration & AC - Assistant Engineer

70% to pass

When recovering the remaining R-134a refrigerant from the centrifugal chiller shown in the illustration as a vapor using the recovery unit’s compressor, in addition to opening valves "1a", "1b", and the compressor suction and discharge isolation valves, which of the following would be the correct valve lineup? Illustration GS-RA-28

Diagram for USCG Refrigeration Assistant: When recovering the remaining R-134a refrigerant from the centrifugal chiller...
Avalves "2", "5", "7", "8", and "10" open; valves "3", "4", and "6" closed
Bvalves "3", "4", and "6" open; valves "2", "5", "7", "8", and "10" closed
Cvalves "3", "4", "7", "6" and "10" open; valves "2", "5", and "8" closed
Dvalves "3", "5", and "6" open; valves "2", "4", "7", "8", and "10" closed
AI Explanation

The correct answer is B) valves "3", "4", and "6" open; valves "2", "5", "7", "8", and "10" closed. This is the correct answer because when recovering the remaining R-134a refrigerant from the centrifugal chiller as a vapor, the recovery process requires the compressor suction and discharge isolation valves to be open, along with valves "3", "4", and "6". This allows the refrigerant vapor to be drawn into the recovery unit's compressor for proper containment and disposal. The other answer choices are incorrect because they either have the wrong valves open or closed, which would not allow the proper flow of refrigerant vapor to the recovery unit for safe handling.

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Official Resources
46 CFR Machinery & Electrical 46 CFR Engineering USCG National Maritime Center
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