HVAC Compressors and Condensing Units

Question 1

What is the primary function of a compressor in a refrigeration cycle?

Accepted Answer

Increase the pressure and temperature of the refrigerant vapor

Answer

Remove heat from the refrigerant

Answer

Expand the refrigerant to lower its temperature

Answer

Remove moisture from the refrigerant

Question 2

Which type of compressor uses a piston moving back and forth inside a cylinder to compress refrigerant?

Accepted Answer

Reciprocating compressor

Answer

Scroll compressor

Answer

Centrifugal compressor

Answer

Rotary compressor

Question 3

What is the suction line in a refrigeration system?

Accepted Answer

The line carrying low-pressure vapor from the evaporator to the compressor

Answer

The line carrying high-pressure liquid from the condenser

Answer

The line carrying discharge gas to the condenser

Answer

The line connecting the metering device to the evaporator

Question 4

Which type of compressor uses two interlocking spiral-shaped scrolls to compress refrigerant?

Accepted Answer

Scroll compressor

Answer

Reciprocating compressor

Answer

Screw compressor

Answer

Centrifugal compressor

Question 5

What does a high-pressure lockout on a condensing unit protect against?

Accepted Answer

Excessively high discharge pressure that could damage the compressor

Answer

Low refrigerant charge

Answer

Low ambient temperature operation

Answer

Inadequate airflow across the evaporator coil

Question 6

What is 'liquid slugging' in a compressor?

Accepted Answer

Liquid refrigerant entering the compressor and causing mechanical damage

Answer

Refrigerant oil circulating through the system

Answer

A slow-running compressor due to low voltage

Answer

Refrigerant migrating to the oil sump during the off cycle

Question 7

On an air-cooled condensing unit, what is the purpose of the condenser fan?

Accepted Answer

Force outdoor air across the condenser coil to reject heat

Answer

Draw return air across the evaporator coil

Answer

Circulate refrigerant through the condenser

Answer

Cool the compressor motor windings