HVAC CONTRACTOR LICENSING EXAMINER EXAM QUESTIONS AND
ANSWERS (VERIFIED ANSWERS) PLUS RATIONALE 2025/2026 Q&A/
INSTANDOWNLOAD PDF
1. Which of the following gases is most commonly used as a refrigerant in modern
residential air conditioning systems?
A. Ammonia (NH₃)
B. R-22
C. R-410A
D. Carbon dioxide (CO₂)
Correct Answer: C. R-410A — It is widely used in modern systems due to its efficiency and
compliance with environmental regulations compared to R-22.
2. What does the term “superheat” refer to in refrigeration systems?
A. Temperature above the condenser pressure
B. Temperature above the boiling point of the refrigerant vapor
C. The difference between condensing and evaporating temperature
D. Subcooling the refrigerant
Correct Answer: B — Superheat is the temperature of vapor refrigerant above its boiling
(saturation) temperature at a given pressure.
3. What component in an HVAC system controls the flow of refrigerant into the
evaporator?
A. Compressor
B. Expansion valve
C. Condenser coil
D. Filter drier
Correct Answer: B — The expansion valve meters refrigerant into the evaporator at the proper
rate to control superheat.
4. The primary function of the condenser coil in a refrigeration system is to:
A. Absorb heat from indoor air
B. Reject heat to the outdoor air
,C. Increase refrigerant pressure
D. Reduce system superheat
Correct Answer: B — The condenser removes heat from the refrigerant and expels it to the
outdoor environment.
5. Which of the following types of compressors is most commonly used in residential split
systems?
A. Screw compressor
B. Centrifugal compressor
C. Reciprocating compressor
D. Scroll compressor
Correct Answer: D — Scroll compressors are efficient, quiet, and reliable for residential HVAC
systems.
6. What is the main function of the evaporator coil?
A. Reject heat outdoors
B. Absorb heat from the conditioned space
C. Compress refrigerant
D. Regulate system pressure
Correct Answer: B — The evaporator coil absorbs heat from indoor air, cooling and
dehumidifying it.
7. The correct pressure-temperature relationship in a refrigeration system is governed by:
A. Charles’s Law
B. Dalton’s Law
C. The Refrigerant Pressure-Temperature Chart
D. Boyle’s Law
Correct Answer: C — Each refrigerant has a specific P-T chart used to diagnose and set system
pressures.
8. What is the typical voltage for residential HVAC control circuits?
A. 12 volts
B. 24 volts
C. 120 volts
D. 240 volts
Correct Answer: B — Most residential control systems use 24V for thermostats and relays.
, 9. What safety device prevents the compressor from operating with insufficient
refrigerant?
A. High-pressure switch
B. Low-pressure switch
C. Overload relay
D. Thermal fuse
Correct Answer: B — A low-pressure switch opens the circuit if refrigerant pressure drops
below safe limits.
10. Which of the following best describes “subcooling”?
A. Cooling the liquid refrigerant below its condensation temperature
B. Increasing vapor temperature
C. Heating the suction gas
D. Reducing system superheat
Correct Answer: A — Subcooling ensures that only liquid refrigerant reaches the expansion
device.
11. What does SEER stand for?
A. System Energy Efficiency Ratio
B. Seasonal Energy Efficiency Ratio
C. Standard Energy Efficiency Rate
D. Seasonal Equipment Efficiency Rating
Correct Answer: B — SEER measures the cooling efficiency of air conditioners over a typical
cooling season.
12. What is the main purpose of a filter drier in a refrigeration system?
A. To control refrigerant flow
B. To remove moisture and contaminants
C. To increase compressor efficiency
D. To prevent overheating
Correct Answer: B — Filter driers remove moisture and debris, protecting system components.
13. What tool is used to measure the superheat or subcooling in a system?
A. Clamp meter
B. Thermometer and manifold gauge set
C. Psychrometer
D. Vacuum pump
ANSWERS (VERIFIED ANSWERS) PLUS RATIONALE 2025/2026 Q&A/
INSTANDOWNLOAD PDF
1. Which of the following gases is most commonly used as a refrigerant in modern
residential air conditioning systems?
A. Ammonia (NH₃)
B. R-22
C. R-410A
D. Carbon dioxide (CO₂)
Correct Answer: C. R-410A — It is widely used in modern systems due to its efficiency and
compliance with environmental regulations compared to R-22.
2. What does the term “superheat” refer to in refrigeration systems?
A. Temperature above the condenser pressure
B. Temperature above the boiling point of the refrigerant vapor
C. The difference between condensing and evaporating temperature
D. Subcooling the refrigerant
Correct Answer: B — Superheat is the temperature of vapor refrigerant above its boiling
(saturation) temperature at a given pressure.
3. What component in an HVAC system controls the flow of refrigerant into the
evaporator?
A. Compressor
B. Expansion valve
C. Condenser coil
D. Filter drier
Correct Answer: B — The expansion valve meters refrigerant into the evaporator at the proper
rate to control superheat.
4. The primary function of the condenser coil in a refrigeration system is to:
A. Absorb heat from indoor air
B. Reject heat to the outdoor air
,C. Increase refrigerant pressure
D. Reduce system superheat
Correct Answer: B — The condenser removes heat from the refrigerant and expels it to the
outdoor environment.
5. Which of the following types of compressors is most commonly used in residential split
systems?
A. Screw compressor
B. Centrifugal compressor
C. Reciprocating compressor
D. Scroll compressor
Correct Answer: D — Scroll compressors are efficient, quiet, and reliable for residential HVAC
systems.
6. What is the main function of the evaporator coil?
A. Reject heat outdoors
B. Absorb heat from the conditioned space
C. Compress refrigerant
D. Regulate system pressure
Correct Answer: B — The evaporator coil absorbs heat from indoor air, cooling and
dehumidifying it.
7. The correct pressure-temperature relationship in a refrigeration system is governed by:
A. Charles’s Law
B. Dalton’s Law
C. The Refrigerant Pressure-Temperature Chart
D. Boyle’s Law
Correct Answer: C — Each refrigerant has a specific P-T chart used to diagnose and set system
pressures.
8. What is the typical voltage for residential HVAC control circuits?
A. 12 volts
B. 24 volts
C. 120 volts
D. 240 volts
Correct Answer: B — Most residential control systems use 24V for thermostats and relays.
, 9. What safety device prevents the compressor from operating with insufficient
refrigerant?
A. High-pressure switch
B. Low-pressure switch
C. Overload relay
D. Thermal fuse
Correct Answer: B — A low-pressure switch opens the circuit if refrigerant pressure drops
below safe limits.
10. Which of the following best describes “subcooling”?
A. Cooling the liquid refrigerant below its condensation temperature
B. Increasing vapor temperature
C. Heating the suction gas
D. Reducing system superheat
Correct Answer: A — Subcooling ensures that only liquid refrigerant reaches the expansion
device.
11. What does SEER stand for?
A. System Energy Efficiency Ratio
B. Seasonal Energy Efficiency Ratio
C. Standard Energy Efficiency Rate
D. Seasonal Equipment Efficiency Rating
Correct Answer: B — SEER measures the cooling efficiency of air conditioners over a typical
cooling season.
12. What is the main purpose of a filter drier in a refrigeration system?
A. To control refrigerant flow
B. To remove moisture and contaminants
C. To increase compressor efficiency
D. To prevent overheating
Correct Answer: B — Filter driers remove moisture and debris, protecting system components.
13. What tool is used to measure the superheat or subcooling in a system?
A. Clamp meter
B. Thermometer and manifold gauge set
C. Psychrometer
D. Vacuum pump
