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
An internal bypass is provided on some hydraulic system suction strainers to help reduce the possibility of （）.
The rate of heat transfer between the hot and cold fluids passing through a shell-and-tube type heat exchanger will （）.
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?（）
An excessive charge of refrigerant in an air-cooled refrigeration system can cause （）.
On tank vessels equipped with power operated cargo tank valves, the type of power operator most commonly used is （）.
Which of the following statements is correct concerning heat transfer?（）
The amount of fluid friction or internal friction inherent in a mineral lubricating oil is reflected as a measure of its （）.
Who is responsible for ensuring that someone is assigned to close the watertight doors in an emergency?（）
If the suction pressure at the refrigeration compressor is below normal, the cause can be（）.