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

The compressor raises the pressure of the low-pressure refrigerant vapor, which also raises its temperature so heat can be rejected in the condenser.

Question 2

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

Accepted Answer

Reciprocating compressor

Answer

A reciprocating compressor uses pistons driven by a crankshaft to compress refrigerant through back-and-forth (reciprocating) motion.

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 suction line carries low-pressure refrigerant vapor from the evaporator back to the compressor inlet.

Question 4

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

Accepted Answer

Scroll compressor

Answer

A scroll compressor uses two interlocking spiral elements — one fixed and one orbiting — to trap and compress refrigerant.

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

A high-pressure lockout switch shuts down the unit when discharge pressure exceeds safe limits, preventing compressor damage from excessive head pressure.

HVAC - Heating, Ventilation, and Air Conditioning Practice Test

HVAC - Heating, Ventilation, and Air Conditioning Practice Test

HVAC Compressors and Condensing Units