Tennessee HVAC Contractor Examination (CMC-C
Heating, Ventilation & Air Conditioning) Questions
and Correct Answers (Verified Answers) Plus
Rationale 2027 Q&A| Instant Download Pdf
1. What is the primary purpose of a properly sized HVAC system?
A. To maximize equipment cycling
B. To provide adequate heating and cooling while maintaining comfort
and efficiency
C. To eliminate the need for ductwork
D. To operate continuously at maximum capacity
Answer: B. To provide adequate heating and cooling while
maintaining comfort and efficiency
Rationale: Proper sizing allows the system to meet the building’s
heating and cooling loads without excessive cycling or unnecessary
energy consumption. Oversized equipment can reduce
dehumidification and comfort, while undersized equipment may fail to
maintain the desired indoor conditions.
, 2. Which instrument is commonly used to measure static pressure in
an HVAC duct system?
A. Psychrometer
B. Manometer
C. Thermocouple
D. Megohmmeter
Answer: B. Manometer
Rationale: A manometer measures pressure differences, including
duct static pressure. Static-pressure measurements can help identify
restrictions, dirty filters, improperly sized ductwork, or other airflow
problems.
3. What is the primary function of a thermostat in a conventional
HVAC system?
A. Compress refrigerant
B. Measure duct pressure
C. Sense space temperature and control system operation
D. Remove moisture from refrigerant
Answer: C. Sense space temperature and control system operation
,Rationale: A thermostat senses the temperature of the conditioned
space and sends control signals to initiate or terminate heating or
cooling. Modern thermostats may also control fan operation, staging,
and other functions.
4. In a vapor-compression refrigeration system, which component
raises the pressure of the refrigerant vapor?
A. Evaporator
B. Condenser
C. Compressor
D. Expansion device
Answer: C. Compressor
Rationale: The compressor receives low-pressure refrigerant vapor
from the evaporator and compresses it into a high-pressure, high-
temperature vapor. This pressure increase allows heat to be rejected
through the condenser.
5. What is the primary purpose of the condenser in a refrigeration
system?
, A. Absorb heat from the conditioned space
B. Reject heat from the refrigerant
C. Reduce refrigerant pressure before the evaporator
D. Increase indoor humidity
Answer: B. Reject heat from the refrigerant
Rationale: In cooling mode, the condenser releases heat absorbed by
the refrigerant in the evaporator, along with the heat added by
compressor operation. The refrigerant changes from a high-pressure
vapor to a high-pressure liquid.
6. Which refrigeration component meters refrigerant entering the
evaporator?
A. Compressor
B. Condenser fan
C. Expansion device
D. Receiver
Answer: C. Expansion device
Rationale: The expansion device controls refrigerant flow into the
evaporator and produces a pressure drop. This pressure reduction
Heating, Ventilation & Air Conditioning) Questions
and Correct Answers (Verified Answers) Plus
Rationale 2027 Q&A| Instant Download Pdf
1. What is the primary purpose of a properly sized HVAC system?
A. To maximize equipment cycling
B. To provide adequate heating and cooling while maintaining comfort
and efficiency
C. To eliminate the need for ductwork
D. To operate continuously at maximum capacity
Answer: B. To provide adequate heating and cooling while
maintaining comfort and efficiency
Rationale: Proper sizing allows the system to meet the building’s
heating and cooling loads without excessive cycling or unnecessary
energy consumption. Oversized equipment can reduce
dehumidification and comfort, while undersized equipment may fail to
maintain the desired indoor conditions.
, 2. Which instrument is commonly used to measure static pressure in
an HVAC duct system?
A. Psychrometer
B. Manometer
C. Thermocouple
D. Megohmmeter
Answer: B. Manometer
Rationale: A manometer measures pressure differences, including
duct static pressure. Static-pressure measurements can help identify
restrictions, dirty filters, improperly sized ductwork, or other airflow
problems.
3. What is the primary function of a thermostat in a conventional
HVAC system?
A. Compress refrigerant
B. Measure duct pressure
C. Sense space temperature and control system operation
D. Remove moisture from refrigerant
Answer: C. Sense space temperature and control system operation
,Rationale: A thermostat senses the temperature of the conditioned
space and sends control signals to initiate or terminate heating or
cooling. Modern thermostats may also control fan operation, staging,
and other functions.
4. In a vapor-compression refrigeration system, which component
raises the pressure of the refrigerant vapor?
A. Evaporator
B. Condenser
C. Compressor
D. Expansion device
Answer: C. Compressor
Rationale: The compressor receives low-pressure refrigerant vapor
from the evaporator and compresses it into a high-pressure, high-
temperature vapor. This pressure increase allows heat to be rejected
through the condenser.
5. What is the primary purpose of the condenser in a refrigeration
system?
, A. Absorb heat from the conditioned space
B. Reject heat from the refrigerant
C. Reduce refrigerant pressure before the evaporator
D. Increase indoor humidity
Answer: B. Reject heat from the refrigerant
Rationale: In cooling mode, the condenser releases heat absorbed by
the refrigerant in the evaporator, along with the heat added by
compressor operation. The refrigerant changes from a high-pressure
vapor to a high-pressure liquid.
6. Which refrigeration component meters refrigerant entering the
evaporator?
A. Compressor
B. Condenser fan
C. Expansion device
D. Receiver
Answer: C. Expansion device
Rationale: The expansion device controls refrigerant flow into the
evaporator and produces a pressure drop. This pressure reduction
