ACR 202 Midterm Exam.

Which of the following is not a major component of the Refrigeration cycle?

• compressor

• condenser

• evaporator

• suction-line drier

To throttle or regulate the flow of fluid as opposed to just starting or stopping it is called .............

• pulsing

• modulating

• rationing

• mixing

The purpose of the crankcase pressure regulating-valve is to

• maintain constant pressure in the crankcase.

• maintain constant pressure in the evaporator.

• prevent a compressor from going into a vacuum.

• prevent a compressor overload condition.

The ........... valve can move in very small increments to either open or close the suction line in response to the discharge air temperature of a refrigerated case.

• electronic evaporator pressure regulator

• thermostatic expansion

• electronic expansion

• crankcase pressure regulator

An automatic pump down system may be used to

• maintain a constant evaporator pressure during low load conditions.

• raise the head pressure during low ambient conditions.

• prevents surges of liquid refrigerant from entering the compressor during start up.

• prevents liquid refrigerant from being trapped in the receiver.

On a one-time or non-short-cycle pump down system

• a leaking solenoid valve or discharge valve will cause the system to turn back on.

• only the thermostat calling again for cooling will take the system out of pump down.

• the refrigerant is stored in the receiver and must be manually released back into the system.

• once the system has been pumped down, it will lock out, requiring service.

Two types of relief valves are ...............

• check and spring-loaded

• manual and ball

• spring-loaded and one-time

• one-time and multiuse

To prevent the head pressure from dropping to the point where the expansion valve not feed correctly

• a pump down system is used.

• an evaporator pressure regulator is used.

• low ambient controls are used.

• a high pressure control is used.

Which of the following is not a method of low ambient control on air-cooled equipment?

• Modulating TXV

• Fan-cycling controls

• Condenser flooding

• Fan speed control

Which of the following is used as a protection against low charge or as a temperature control for some refrigeration evaporators?

• Oil safety switch

• Thermostat

• High-pressure switch

• Low-pressure switch