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 head pressure of a reciprocating refrigeration compressor is excessive, （）.
An internal bypass is provided on some hydraulic system suction strainers to help reduce the possibility of （）.
A salinity indicator is used to determine the （）.
Which of the problems listed would came the discharge temperature of an R-12 refrigeration compressor to increase?（）
One cause of high head pressure occurring in a refrigeration system can be （）.
Thermostatic expansion valves can be adjusted for （）.
The output volume of a positive fixed displacement pump can be changed only by （）.
Who is responsible for ensuring that someone is assigned to close the watertight doors in an emergency?（）
If you are given the job of adding hydraulic fluid to a mooring winch, and are not certain as to the type of fluid to use, you should （）.
Pitting in the suction areas of a centrifugal pump bronze impeller is usually caused by （）.