NC Plumbing, Heating & Fire Sprinkler Contractors
Board – Heating (HVAC) Contractor Examination
(Group 2) Questions and Correct Answers (Verified
Answers) Plus Rationale 2027 Q&A| Instant
Download Pdf
Question 1
What is the primary purpose of a thermostat in a conventional HVAC
system?
A. To increase refrigerant pressure
B. To control airflow through the duct system
C. To sense space temperature and initiate heating or cooling
operation
D. To remove moisture from the refrigerant
Rationale: A thermostat monitors the temperature of the conditioned
space and signals the heating or cooling equipment when operation is
needed. It does not directly control refrigerant pressure or humidity.
Question 2
,Which component in a vapor-compression refrigeration system
removes heat from the conditioned space?
A. Condenser
B. Compressor
C. Expansion device
D. Evaporator
Rationale: The evaporator absorbs heat from the air or another
medium being cooled. Refrigerant entering the evaporator at low
pressure and temperature changes state as it absorbs heat.
Question 3
What is the primary function of the compressor in a refrigeration
system?
A. Lower refrigerant temperature
B. Raise refrigerant pressure and circulate refrigerant through the
system
C. Remove moisture from indoor air
D. Reduce condenser airflow
Rationale: The compressor draws low-pressure refrigerant vapor from
the evaporator and compresses it into a high-pressure, high-
temperature vapor before sending it to the condenser.
,Question 4
A condenser in an air-conditioning system primarily:
A. Absorbs heat from the occupied space
B. Reduces electrical voltage
C. Rejects heat from the refrigerant to the surrounding environment
D. Controls the thermostat setting
Rationale: The condenser removes heat from the refrigerant, including
the heat absorbed in the evaporator and the compressor's heat of
compression. The refrigerant typically condenses from vapor to liquid
in this process.
Question 5
What is the purpose of an expansion valve or other metering device?
A. Increase compressor speed
B. Reduce refrigerant pressure and regulate refrigerant flow into the
evaporator
C. Increase condenser temperature
D. Remove contaminants from ductwork
Rationale: The metering device creates a pressure drop between the
high and low sides and controls the amount of refrigerant entering
the evaporator.
, Question 6
What does superheat represent in a refrigeration system?
A. The temperature of liquid refrigerant below its boiling point
B. The pressure difference between the condenser and evaporator
C. The temperature of vapor above its saturation temperature at a
given pressure
D. The temperature of the compressor casing
Rationale: Superheat is the amount by which vapor temperature
exceeds its saturation temperature at the measured pressure. It is
useful for evaluating evaporator operation and protecting the
compressor from liquid refrigerant.
Question 7
What does subcooling indicate?
A. Vapor temperature above saturation
B. Liquid refrigerant temperature below its saturation temperature at
a given pressure
C. Compressor discharge temperature
D. Indoor air temperature below setpoint
Board – Heating (HVAC) Contractor Examination
(Group 2) Questions and Correct Answers (Verified
Answers) Plus Rationale 2027 Q&A| Instant
Download Pdf
Question 1
What is the primary purpose of a thermostat in a conventional HVAC
system?
A. To increase refrigerant pressure
B. To control airflow through the duct system
C. To sense space temperature and initiate heating or cooling
operation
D. To remove moisture from the refrigerant
Rationale: A thermostat monitors the temperature of the conditioned
space and signals the heating or cooling equipment when operation is
needed. It does not directly control refrigerant pressure or humidity.
Question 2
,Which component in a vapor-compression refrigeration system
removes heat from the conditioned space?
A. Condenser
B. Compressor
C. Expansion device
D. Evaporator
Rationale: The evaporator absorbs heat from the air or another
medium being cooled. Refrigerant entering the evaporator at low
pressure and temperature changes state as it absorbs heat.
Question 3
What is the primary function of the compressor in a refrigeration
system?
A. Lower refrigerant temperature
B. Raise refrigerant pressure and circulate refrigerant through the
system
C. Remove moisture from indoor air
D. Reduce condenser airflow
Rationale: The compressor draws low-pressure refrigerant vapor from
the evaporator and compresses it into a high-pressure, high-
temperature vapor before sending it to the condenser.
,Question 4
A condenser in an air-conditioning system primarily:
A. Absorbs heat from the occupied space
B. Reduces electrical voltage
C. Rejects heat from the refrigerant to the surrounding environment
D. Controls the thermostat setting
Rationale: The condenser removes heat from the refrigerant, including
the heat absorbed in the evaporator and the compressor's heat of
compression. The refrigerant typically condenses from vapor to liquid
in this process.
Question 5
What is the purpose of an expansion valve or other metering device?
A. Increase compressor speed
B. Reduce refrigerant pressure and regulate refrigerant flow into the
evaporator
C. Increase condenser temperature
D. Remove contaminants from ductwork
Rationale: The metering device creates a pressure drop between the
high and low sides and controls the amount of refrigerant entering
the evaporator.
, Question 6
What does superheat represent in a refrigeration system?
A. The temperature of liquid refrigerant below its boiling point
B. The pressure difference between the condenser and evaporator
C. The temperature of vapor above its saturation temperature at a
given pressure
D. The temperature of the compressor casing
Rationale: Superheat is the amount by which vapor temperature
exceeds its saturation temperature at the measured pressure. It is
useful for evaluating evaporator operation and protecting the
compressor from liquid refrigerant.
Question 7
What does subcooling indicate?
A. Vapor temperature above saturation
B. Liquid refrigerant temperature below its saturation temperature at
a given pressure
C. Compressor discharge temperature
D. Indoor air temperature below setpoint
