单选题A refrigeration system compressor crankcase is sweating or unusually coldThis is an indication of（）.Aa shortage of refrigerant in the systemBair in the systemCan accumulation of liquid refrigerant in the crankcaseDa shortage of oil in the crankcase
单选题
A refrigeration system compressor crankcase is sweating or unusually coldThis is an indication of（）.
A
a shortage of refrigerant in the system
B
air in the system
C
an accumulation of liquid refrigerant in the crankcase
D
a shortage of oil in the crankcase
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