單項選擇題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


您可能感興趣的試卷

你可能感興趣的試題

1.單項選擇題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

2.單項選擇題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

3.單項選擇題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

5.單項選擇題Which of the conditions listed will cause a refrigeration compressor to run constantly without simultaneously decreasing the temperature in the refrigerated space?（）

A.Shortage of refrigerant oil
B.Slight shortage of refrigerant
C.Excessive condenser cooling water flow
D.Faulty expansion valve