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
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
A.restriction in refrigerant piping
B.air and non-condensable gases in the condenser
C.water in the refrigerant
D.flooding back of liquid refrigerant from the evaporator
最新试题
The rate of heat transfer from a hot region to a cold region is affected most by the ().
Heavy wear in a particular area of the inner circumference of a packing ring may be caused by ().
An excessive charge of refrigerant in an air-cooled refrigeration system can cause ().
The general purpose of a heat exchanger is to ().
If the thermal bulb of an expansion valve is incorrectly placed at the center of the coil instead of the end, it will ().
One cause of high head pressure occurring in a refrigeration system can be ().
Which of the following problems could cause the high pressure cutout switch to shut down the compressor in a refrigeration system?()
Which of the following statements is correct concerning heat transfer?()
A salinity indicator is used to determine the ().
If the relief valve on the discharge side of a hydraulic pump lifts, the cause could be ().