Unit 25 Practice Test

The two forces that control the EPR valve are the __________.

• suction line pressure and the evaporator pressure

• liquid line pressure and the suction line pressure

• valve’s spring pressure and the liquid line pressure

• evaporator pressure and the valve’s spring pressure

Refrigerant relief valves come in two different types, ___________.

• spring-loaded and electronic

• electronic and mechanical

• spring-loaded and one-time

• mechanical and one-type

A _________ has a magnetic coil, can be normally open or normally closed, and is frequently used to control fluid flow (liquid or vapor).

• crankcase pressure regulator

• variable frequency drive

• evaporator pressure regulator

• solenoid valve

Pressure switches are used to start and stop electrical current flow to refrigeration components.

• True

• False

A control that can be used as either a low-charge protection or to control space temperature is a __________.

• high-pressure switch

• low-pressure switch

• thermostat

• low ambient control

During an automatic pumpdown, the refrigerant is stored in the ___________.

• condenser and receiver

• evaporator

• receiver

• evaporator and suction line

A ___________ is used to keep the compressor from operating with high head pressure.

• head pressure regulator

• fan-cycling control

• low-pressure control

• high-pressure control

Net oil pressure is the pressure that can be measured at the discharge or outlet of the oil pump.

• True

• False

Any evaporator that operates below 32°F ______________.

• should have a heater in the evaporator to ensure proper oil return

• must have and EPR and a TXV

• requires some form of defrost

• should have a check valve at its outlet to keep up pressure during the off-cycle

A ________ can be used to improve the capacity of the evaporator by subcooling the liquid refrigerant entering it.

• filter drier

• check valve

• refrigerant distributor

• heat exchanger