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
When a refrigeration compressor has developed a high head pressure as a result of a refrigerant overcharge, you should （）.
If you are given the job of adding hydraulic fluid to a mooring winch, and are not certain as to the type of fluid to use, you should （）.
If the viscosity of the liquid being transferred remains constant as the discharge pressure increases, the rotary pump （）.
If the suction pressure at the refrigeration compressor is below normal, the cause can be（）.
A gradual decrease in the discharge pressure of an operating hydraulic pump can be caused by （）.
Which of the following statements is correct concerning heat transfer?（）
Which of the listed pumps is NOT a positive displacement pump?（）
The usual symptoms of cavitation in a centrifugal pump is （）.
A pressure drop through the refrigerant liquid line may cause （）.
Low compressor head pressure in a refrigeration system can be caused by（）.