单项选择题
In the refrigeration system, a shortage of refrigerant is indicated by ().
A.the compressor short cycling on high pressure cut out switch
B.high suction pressure
C.high head pressure
D.bubbles in the sight glass
相关考题
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单项选择题
Which of the following conditions must exist for heat to flow from one object to another?()
A.The two objects must be in physical contact
B.The two objects must be the same size
C.There must be an existing temperature differential
D.There must be an existing weight differential -
单项选择题
A warmer than normal compressor suction line might be caused by ().
A.insufficient lubrication
B.insufficient refrigerant
C.excess refrigerant
D.excessive opening of the expansion valve -
单项选择题
The unloading system on an air compressor will ().
A.increase compressor discharge pressure on demand
B.increase compressor operating speed as necessary
C.allow the motor to turn the compressor opposed only by friction
D.reduce the compressor frictional load when starting
