CH49

A valve that is used to protect the compressor from higher than normal pressure vapor from the suction line is a(n) ____.

CPR

A valve that is used to restrict the flow of refrigerant coming out of the evaporator is a(n) ____.

EPR

All compound systems balance during the Off cycle.

FALSE

An EPR is used to maintain evaporator pressure below suction line pressure.

FALSE

Split systems cannot be custom designed for specific applications.

FALSE

The bulk of the heat absorbed from the conditioned space of a secondary loop refrigeration system is in the form of latent heat.

FALSE

The compressor motors used in compound systems do not need to be able to start under load.

FALSE

The low-stage subsystem and the high-stage subsystem of a cascade system operate independently and at different times.

FALSE

A liquid receiver service valve is used to isolate the liquid receiver from the rest of the system.

TRUE

Bypassed hot gas can help to prevent compressor damage and short cycling of the system.

TRUE

EPRs are used on multiple-evaporator systems in which one or more evaporators maintain a different temperature from one or more other evaporators.

TRUE

In a cascade system, the high-stage evaporator cools the refrigerant in the low-stage condenser.

TRUE

System controls can turn on or off individual compressors in a multiple compressor system.

TRUE

The components of a split system are purchased separately and assembled at the job site.

TRUE

The refrigerant in each subsystem of a cascade system is not intended to mix with the refrigerant in the other subsystems.

TRUE

Which of the following statements regarding cascade systems is true?

They operate at very low temperatures so the refrigerant must be very dry.

The refrigerant in the secondary loop of a secondary loop refrigeration system ___

absorbs heat but does not evaporate

A secondary loop system uses a(n) ____ to trap air circulating with the secondary refrigerant.

air separator

If the heat load is light, ____.

an oversized system will tend to short cycle

A secondary loop refrigeration system controls flow using a ____.

balancing valve

A multistage system that consists of two or more separate refrigeration subsystems that work together to multiply cooling effect is a ____.

cascade refrigeration system

Secondary loop systems use ____ to move the secondary refrigerant.

circulating pumps

A compound refrigeration system can produce such low temperatures because it uses two ____

compressors connected in series

A valve that protects the compressor from higher than normal pressure vapor from the suction line is a(n) ____

crankcase pressure regulator (CPR)

As the flow of secondary refrigerant increases, the temperature of the conditioned space ____.

decreases

The valve used to allow hot-gas refrigerant from the discharge line to enter the evaporator and flow into the low side of the system is a hot-gas ____ valve.

defrost

A valve that restricts the flow of refrigerant coming out of one evaporator in a multiple-evaporator system is a(n) ____.

evaporator pressure regulator (EPR)

A valve used to reduce the temperature of the hot gas by allowing liquid refrigerant from the liquid line to mix with and cool the bypassed hot refrigerant vapor is a ____.

liquid injection valve

When a high-side service valve is located between a condenser and a refrigerant metering device, it may be referred to as a ____.

liquid line service valve

A commercial refrigeration system that is designed, built, and shipped by the manufacturer is referred to as a ____ system.

packaged

Refrigeration units designed, built, and shipped by the manufacturer are referred to as ____ systems.

packaged

A crankcase heater is used to ___

prevent refrigerant from condensing into liquid

The primary valve used to pump down the system into the liquid receiver is the liquid ____.

receiver service valve

A service valve connected to the inlet or the low side of the compressor is a ____.

suction service valve

In a system in which hot gas from the compressor is bypassed directly to the evaporator inlet, ____.

the hot gas increases the load the system can continue running while maintaining the desired temperature temperature and humidity can be controlled more precisely Correct! All of the above.

After an outdoor compressor has cycled off and when ambient temperature is very low, ____.

the refrigerant inside the compressor could condense into liquid there is a danger of slugging and damage that may lead to failure a crankcase heater may be used to prevent the refrigerant from condensing all of the above

A flexible section of piping that isolates the vibrations produced by the compressor is called a ____.

vibration absorber

A hot-gas bypass valve ____

warms the cool suction gas, raising the pressure in the suction line is connected by its inlet to the discharge line opens if the low-side pressure becomes excessively low Correct! All of the above.