Ct Hvac Contractor Exam Questions
And Correct Answers (Verified Answers)
Plus Rationales 2026 Q&A| Instant
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1. What is the primary function of an HVAC system?
A. To generate electricity
B. To provide heating, ventilation, and air conditioning
C. To control water flow
D. To detect fire
B. To provide heating, ventilation, and air conditioning
Rationale: The core purpose of HVAC systems is to maintain indoor
comfort by controlling temperature, humidity, and air quality.
2. Which refrigerant is commonly used in modern residential air
conditioning systems due to environmental regulations?
A. R-22
B. R-410A
C. Ammonia
D. R-12
B. R-410A
Rationale: R-410A is widely used as a replacement for R-22 because
it has zero ozone depletion potential.
3. What is the function of a compressor in a refrigeration cycle?
A. To cool the refrigerant
B. To increase the refrigerant pressure and temperature
C. To filter the air
D. To remove humidity
B. To increase the refrigerant pressure and temperature
Rationale: The compressor raises the pressure and temperature of the
refrigerant to allow heat transfer in the condenser.
,4. What does SEER stand for in air conditioning systems?
A. Seasonal Energy Efficiency Ratio
B. Standard Electrical Energy Rating
C. System Energy Evaporation Ratio
D. Seasonal Environmental Efficiency Rating
A. Seasonal Energy Efficiency Ratio
Rationale: SEER measures the cooling efficiency of an air
conditioner over a typical cooling season.
5. Which type of heat pump is most suitable for colder climates?
A. Air-source heat pump
B. Ground-source (geothermal) heat pump
C. Water-source heat pump
D. Evaporative heat pump
B. Ground-source (geothermal) heat pump
Rationale: Ground-source heat pumps maintain higher efficiency in
cold climates because the ground temperature is more stable than air
temperature.
6. In duct design, what is the primary purpose of a plenum?
A. To filter air
B. To distribute airflow evenly to branch ducts
C. To reduce humidity
D. To compress air
B. To distribute airflow evenly to branch ducts
Rationale: A plenum serves as a central distribution area for
conditioned air in HVAC ductwork.
7. What is the typical recommended indoor humidity range for comfort?
A. 10–20%
B. 30–50%
C. 60–80%
D. 80–90%
B. 30–50%
Rationale: Maintaining 30–50% humidity improves comfort and
reduces risks of mold growth.
8. What type of expansion device is commonly used in modern residential
AC units?
A. Thermostatic expansion valve (TXV)
B. Capillary tube
, C. Manual expansion valve
D. Orifice plate
A. Thermostatic expansion valve (TXV)
Rationale: TXVs regulate refrigerant flow according to load,
improving efficiency and performance.
9. Which of the following is a sign that an HVAC system is low on
refrigerant?
A. High airflow
B. Frost on the evaporator coil
C. Warm air from vents
D. High SEER rating
B. Frost on the evaporator coil
Rationale: Low refrigerant causes the evaporator coil temperature to
drop excessively, leading to frost formation.
10. What is the function of a condenser in a refrigeration system?
A. Absorb heat from indoors
B. Reject heat to the outdoors
C. Compress refrigerant
D. Filter air
B. Reject heat to the outdoors
Rationale: The condenser transfers heat absorbed indoors to the
outside environment.
11. Which gas is typically used in detecting leaks in HVAC systems?
A. Helium
B. Carbon monoxide
C. Nitrogen
D. Sulfur hexafluoride
D. Sulfur hexafluoride
Rationale: SF6 is inert and easily detectable, making it useful for
leak detection.
12. Which code regulates HVAC installation safety and practices in
most jurisdictions?
A. National Electrical Code (NEC)
B. International Building Code (IBC)
C. International Mechanical Code (IMC)
D. Fire Code
C. International Mechanical Code (IMC)
And Correct Answers (Verified Answers)
Plus Rationales 2026 Q&A| Instant
Download Pdf
1. What is the primary function of an HVAC system?
A. To generate electricity
B. To provide heating, ventilation, and air conditioning
C. To control water flow
D. To detect fire
B. To provide heating, ventilation, and air conditioning
Rationale: The core purpose of HVAC systems is to maintain indoor
comfort by controlling temperature, humidity, and air quality.
2. Which refrigerant is commonly used in modern residential air
conditioning systems due to environmental regulations?
A. R-22
B. R-410A
C. Ammonia
D. R-12
B. R-410A
Rationale: R-410A is widely used as a replacement for R-22 because
it has zero ozone depletion potential.
3. What is the function of a compressor in a refrigeration cycle?
A. To cool the refrigerant
B. To increase the refrigerant pressure and temperature
C. To filter the air
D. To remove humidity
B. To increase the refrigerant pressure and temperature
Rationale: The compressor raises the pressure and temperature of the
refrigerant to allow heat transfer in the condenser.
,4. What does SEER stand for in air conditioning systems?
A. Seasonal Energy Efficiency Ratio
B. Standard Electrical Energy Rating
C. System Energy Evaporation Ratio
D. Seasonal Environmental Efficiency Rating
A. Seasonal Energy Efficiency Ratio
Rationale: SEER measures the cooling efficiency of an air
conditioner over a typical cooling season.
5. Which type of heat pump is most suitable for colder climates?
A. Air-source heat pump
B. Ground-source (geothermal) heat pump
C. Water-source heat pump
D. Evaporative heat pump
B. Ground-source (geothermal) heat pump
Rationale: Ground-source heat pumps maintain higher efficiency in
cold climates because the ground temperature is more stable than air
temperature.
6. In duct design, what is the primary purpose of a plenum?
A. To filter air
B. To distribute airflow evenly to branch ducts
C. To reduce humidity
D. To compress air
B. To distribute airflow evenly to branch ducts
Rationale: A plenum serves as a central distribution area for
conditioned air in HVAC ductwork.
7. What is the typical recommended indoor humidity range for comfort?
A. 10–20%
B. 30–50%
C. 60–80%
D. 80–90%
B. 30–50%
Rationale: Maintaining 30–50% humidity improves comfort and
reduces risks of mold growth.
8. What type of expansion device is commonly used in modern residential
AC units?
A. Thermostatic expansion valve (TXV)
B. Capillary tube
, C. Manual expansion valve
D. Orifice plate
A. Thermostatic expansion valve (TXV)
Rationale: TXVs regulate refrigerant flow according to load,
improving efficiency and performance.
9. Which of the following is a sign that an HVAC system is low on
refrigerant?
A. High airflow
B. Frost on the evaporator coil
C. Warm air from vents
D. High SEER rating
B. Frost on the evaporator coil
Rationale: Low refrigerant causes the evaporator coil temperature to
drop excessively, leading to frost formation.
10. What is the function of a condenser in a refrigeration system?
A. Absorb heat from indoors
B. Reject heat to the outdoors
C. Compress refrigerant
D. Filter air
B. Reject heat to the outdoors
Rationale: The condenser transfers heat absorbed indoors to the
outside environment.
11. Which gas is typically used in detecting leaks in HVAC systems?
A. Helium
B. Carbon monoxide
C. Nitrogen
D. Sulfur hexafluoride
D. Sulfur hexafluoride
Rationale: SF6 is inert and easily detectable, making it useful for
leak detection.
12. Which code regulates HVAC installation safety and practices in
most jurisdictions?
A. National Electrical Code (NEC)
B. International Building Code (IBC)
C. International Mechanical Code (IMC)
D. Fire Code
C. International Mechanical Code (IMC)
