A.a high suction head
B.rotating rings
C.badly worn bearings
D.a loose stuffing box gland
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A.solenoid valve to seize
B.compressor to hunt
C.formation of flash gas in the liquid line
D.expansion valve to freeze open
A.insufficient condenser cooling water
B.excessive condenser cooling water
C.air in the refrigeration system
D.excessive refrigerant in the system
A.Thermal expansion valve frozen open
B.Suction gas heat exchanger bypassed
C.Condenser clogged or fouled
D.High pressure cutout switch inoperative
A.noise and vibration
B.an increase in discharge pressure
C.an increase in suction pressure
D.lifting of the relief valve
A.insufficient cooling water flow to the condenser
B.a low refrigerant charge in the system
C.the liquid valve is open too much
D.high evaporator superheat
最新試題
A gradual decrease in the discharge pressure of an operating hydraulic pump can be caused by （）.
The output volume of a positive fixed displacement pump can be changed only by （）.
Low compressor head pressure in a refrigeration system can be caused by（）.
The usual symptoms of cavitation in a centrifugal pump is （）.
A salinity indicator is used to determine the （）.
If the head pressure of a reciprocating refrigeration compressor is excessive, （）.
Which of the following problems could cause the high pressure cutout switch to shut down the compressor in a refrigeration system?（）
When a refrigeration compressor has developed a high head pressure as a result of a refrigerant overcharge, you should （）.
Which of the problems listed would came the discharge temperature of an R-12 refrigeration compressor to increase?（）
An increasing head pressure in a refrigeration system, without any corresponding change in the cooling water inlet temperature, would probably be caused by （）.