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
The amount of fluid friction or internal friction inherent in a mineral lubricating oil is reflected as a measure of its （）.
Which of the following statements is correct concerning heat transfer?（）
Which of the following problems could cause the high pressure cutout switch to shut down the compressor in a refrigeration system?（）
The rate of heat transfer from a hot region to a cold region is affected most by the （）.
The output volume of a positive fixed displacement pump can be changed only by （）.
If the relief valve on the discharge side of a hydraulic pump lifts, the cause could be （）.
Which of the problems listed would came the discharge temperature of an R-12 refrigeration compressor to increase?（）
The control mode in which the final control element is moved from one of two flexed positions to the other is known as （）.
Thermostatic expansion valves can be adjusted for （）.
An internal bypass is provided on some hydraulic system suction strainers to help reduce the possibility of （）.