A.They should always be started with the discharge valve closed
B.They should always be started with the discharge valve opened
C.A priming pump is always required to flood the impeller suction
D.They should always be started with the sealing line valves closed
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A.compressor damage from improper lubrication
B.refrigerant absorption by the lubricant
C.increased viscosity in the lubricant
D.carbon deposit on the compressor suction valves
A.Spring-centered valve
B.Unloading valve
C.Three-position valve
D.Two-position valve
A.Expansion valve
B.Condenser
C.Evaporator
D.Compressor
A.The condenser and the expansion valve
B.The king valve and the solenoid valve
C.The compressor and the expansion valve
D.The condenser and the solenoid valve
A.temperature and pressure
B.humidity and temperature
C.pressure and vacuum
D.pressure and humidity
最新試題
The major source of chemical contaminants in hydraulic fluid is （）.
The usual symptoms of cavitation in a centrifugal pump is （）.
The rate of heat transfer from a hot region to a cold region is affected most by the （）.
When the steering gear is in operation, you should （）.
Heavy wear in a particular area of the inner circumference of a packing ring may be caused by （）.
The output volume of a positive fixed displacement pump can be changed only by （）.
The temperature differential occurring between the inlet temperature of the fluid to be cooled and the outlet temperature of the cooling medium in a shell-and-tube heat exchanger is greatest in which of the flow designs listed?（）
A salinity indicator is used to determine the （）.
If the thermal bulb of an expansion valve is incorrectly placed at the center of the coil instead of the end, it will （）.
A pressure drop through the refrigerant liquid line may cause （）.