AR HVACR Heating, Ventilation, AC &
Refrigeration Contractor Exam Questions
and Correct Answers (Verified Answers)
Plus Rationale 2027 Q&A| Instant
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Section 1: HVACR Fundamentals and Refrigeration Principles
Question 1
What is the primary function of a refrigeration system?
A. To generate cold air directly
B. To convert electrical energy into heat only
C. To transfer heat from a lower-temperature area to a higher-
temperature area
D. To eliminate all moisture from the air
,Rationale: A refrigeration system removes heat from a designated
space and transfers it to another location, usually outdoors.
Refrigeration does not create cold; it removes thermal energy. The
compressor, condenser, expansion device, and evaporator work
together to accomplish this heat transfer.
Question 2
Which component of a conventional vapor-compression refrigeration
system absorbs heat from the space being cooled?
A. Condenser
B. Compressor
C. Evaporator
D. Receiver
Rationale: The evaporator absorbs heat from the conditioned space, air,
or process fluid. Refrigerant enters the evaporator at a low pressure and
temperature, absorbs heat, and generally boils into vapor. This heat
absorption produces the desired cooling effect.
Question 3
What is the primary purpose of the compressor in a vapor-compression
refrigeration system?
,A. To reduce refrigerant pressure
B. To raise refrigerant vapor pressure and circulate refrigerant
C. To remove moisture from the conditioned air
D. To convert liquid refrigerant into a low-pressure mixture
Rationale: The compressor draws low-pressure refrigerant vapor from
the evaporator and compresses it to a higher pressure and temperature.
This allows the refrigerant to reject heat in the condenser at a
temperature above that of the surrounding environment. It also
maintains refrigerant circulation through the system.
Question 4
Which component rejects heat from the refrigerant to the surrounding
environment?
A. Evaporator
B. Condenser
C. Expansion valve
D. Suction accumulator
Rationale: The condenser removes heat from the hot, high-pressure
refrigerant vapor discharged by the compressor. As heat is rejected, the
refrigerant typically condenses into a high-pressure liquid. The
, condenser must have sufficient heat-transfer capacity and airflow or
water flow to operate properly.
Question 5
What is the main function of a thermostatic expansion valve (TXV)?
A. To maintain a constant compressor discharge temperature
B. To increase refrigerant pressure before the condenser
C. To regulate refrigerant flow into the evaporator in response to
evaporator outlet superheat
D. To prevent all refrigerant from entering the evaporator
Rationale: A TXV regulates refrigerant flow to maintain a target
evaporator outlet superheat. Its sensing bulb responds to the
temperature of the suction line, while pressure acting on the valve
diaphragm and the valve's spring force help determine the opening.
Proper operation helps use evaporator capacity effectively while
limiting liquid refrigerant return to the compressor.
Question 6
What does superheat describe in a refrigeration system?
A. The temperature of liquid refrigerant below its saturation
temperature
Refrigeration Contractor Exam Questions
and Correct Answers (Verified Answers)
Plus Rationale 2027 Q&A| Instant
Download Pdf
Section 1: HVACR Fundamentals and Refrigeration Principles
Question 1
What is the primary function of a refrigeration system?
A. To generate cold air directly
B. To convert electrical energy into heat only
C. To transfer heat from a lower-temperature area to a higher-
temperature area
D. To eliminate all moisture from the air
,Rationale: A refrigeration system removes heat from a designated
space and transfers it to another location, usually outdoors.
Refrigeration does not create cold; it removes thermal energy. The
compressor, condenser, expansion device, and evaporator work
together to accomplish this heat transfer.
Question 2
Which component of a conventional vapor-compression refrigeration
system absorbs heat from the space being cooled?
A. Condenser
B. Compressor
C. Evaporator
D. Receiver
Rationale: The evaporator absorbs heat from the conditioned space, air,
or process fluid. Refrigerant enters the evaporator at a low pressure and
temperature, absorbs heat, and generally boils into vapor. This heat
absorption produces the desired cooling effect.
Question 3
What is the primary purpose of the compressor in a vapor-compression
refrigeration system?
,A. To reduce refrigerant pressure
B. To raise refrigerant vapor pressure and circulate refrigerant
C. To remove moisture from the conditioned air
D. To convert liquid refrigerant into a low-pressure mixture
Rationale: The compressor draws low-pressure refrigerant vapor from
the evaporator and compresses it to a higher pressure and temperature.
This allows the refrigerant to reject heat in the condenser at a
temperature above that of the surrounding environment. It also
maintains refrigerant circulation through the system.
Question 4
Which component rejects heat from the refrigerant to the surrounding
environment?
A. Evaporator
B. Condenser
C. Expansion valve
D. Suction accumulator
Rationale: The condenser removes heat from the hot, high-pressure
refrigerant vapor discharged by the compressor. As heat is rejected, the
refrigerant typically condenses into a high-pressure liquid. The
, condenser must have sufficient heat-transfer capacity and airflow or
water flow to operate properly.
Question 5
What is the main function of a thermostatic expansion valve (TXV)?
A. To maintain a constant compressor discharge temperature
B. To increase refrigerant pressure before the condenser
C. To regulate refrigerant flow into the evaporator in response to
evaporator outlet superheat
D. To prevent all refrigerant from entering the evaporator
Rationale: A TXV regulates refrigerant flow to maintain a target
evaporator outlet superheat. Its sensing bulb responds to the
temperature of the suction line, while pressure acting on the valve
diaphragm and the valve's spring force help determine the opening.
Proper operation helps use evaporator capacity effectively while
limiting liquid refrigerant return to the compressor.
Question 6
What does superheat describe in a refrigeration system?
A. The temperature of liquid refrigerant below its saturation
temperature
