单项选择题
A.the relief valve should open before the high pressure cutout
B.the relief valve should open and allow the excess refrigerant to flow to the receiver
C.the high pressure cutout switch should operate before the relief valve opens
D.you should close in on the suction valve
单项选择题 A salinity indicator is used to determine the （）.
单项选择题 An increasing head pressure in a refrigeration system, without any corresponding change in the cooling water inlet temperature, would probably be caused by （）.
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?（）