Question 134Refrigeration & AC - Assistant Engineer

The correct answer is B) liquid refrigerant returning to the compressor. When the refrigeration compressor crankcase is sweating or frosting and the compressor is operating with an unusual noise, it is most likely due to liquid refrigerant returning to the compressor. This can happen when there is a problem with the refrigeration system, such as a restriction in the refrigerant line or a malfunctioning expansion valve, causing liquid refrigerant to flow back to the compressor instead of being properly evaporated. This can damage the compressor and lead to premature failure. The other options are incorrect because: A) the compressor running continuously is not the cause of the sweating/frosting and unusual noise, C) a shortage of refrigerant would not cause this issue, and D) short cycling on the high-pressure cutout would not lead to the observed symptoms.