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
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?（）
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?（）
An excessive charge of refrigerant in an air-cooled refrigeration system can cause （）.
A pressure drop through the refrigerant liquid line may cause （）.
When the steering gear is in operation, you should （）.
The general purpose of a heat exchanger is to （）.
An increasing head pressure in a refrigeration system, without any corresponding change in the cooling water inlet temperature, would probably be caused by （）.
Which of the problems listed would came the discharge temperature of an R-12 refrigeration compressor to increase?（）
A salinity indicator is used to determine the （）.