A.noise and vibration
B.an increase in discharge pressure
C.an increase in suction pressure
D.lifting of the relief valve
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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
A.dead band action
B.neutral zone action
C.range
D.on-off action
A.cavitation
B.electrolysis
C.abrasion
D.corrosion
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
A.cause of salt contamination
B.location of salt water contamination
C.chemical makeup of feed-water
D.level of alkalinity in condensate
最新試題
The control mode in which the final control element is moved from one of two flexed positions to the other is known as （）.
The output volume of a positive fixed displacement pump can be changed only by （）.
A salinity indicator is used to determine the （）.
Heavy wear in a particular area of the inner circumference of a packing ring may be caused by （）.
The rate of heat transfer from a hot region to a cold region is affected most by the （）.
If the head pressure of a reciprocating refrigeration compressor is excessive, （）.
When a refrigeration compressor has developed a high head pressure as a result of a refrigerant overcharge, you should （）.
If the suction pressure at the refrigeration compressor is below normal, the cause can be（）.
Which of the listed pumps is NOT a positive displacement pump?（）
An increasing head pressure in a refrigeration system, without any corresponding change in the cooling water inlet temperature, would probably be caused by （）.