单项选择题
A.restriction in refrigerant piping
B.air and non-condensable gases in the condenser
C.water in the refrigerant
D.flooding back of liquid refrigerant from the evaporator
单项选择题 Which of the following problems could cause the high pressure cutout switch to shut down the compressor in a refrigeration system?（）
单项选择题 The general purpose of a heat exchanger is to （）.
单项选择题 The temperature differential occurring between the inlet temperature of the fluid to be cooled and the outlet temperature of the cooling medium in a shell-and-tube heat exchanger is greatest in which of the flow designs listed?（）