Tennessee HVAC Contractor Exam Questions
and Correct Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant Download Pdf
1. What is the primary purpose of a refrigerant in an HVAC system?
A. Increase electrical efficiency
B. Absorb and release heat during phase changes
C. Lubricate compressor components
D. Filter airborne particles
Answer: B
Rationale: Refrigerant is designed to absorb heat at low
pressure/temperature during evaporation and release heat at high
pressure/temperature during condensation, enabling heat transfer
within the system.
2. Which law governs the relationship between pressure and volume
at constant temperature?
A. Boyle’s Law
B. Charles’s Law
,C. Ohm’s Law
D. Dalton’s Law
Answer: A
Rationale: Boyle’s Law states that pressure and volume are inversely
proportional when temperature remains constant.
3. What component removes moisture and contaminants from
refrigerant?
A. Accumulator
B. Expansion valve
C. Filter drier
D. Compressor
Answer: C
Rationale: A filter drier removes moisture, acids, and debris from the
refrigerant to protect system components.
4. What is the function of the compressor in a refrigeration system?
A. Reduce refrigerant temperature
B. Increase refrigerant pressure and temperature
,C. Store refrigerant
D. Measure airflow
Answer: B
Rationale: The compressor compresses low-pressure refrigerant vapor
into high-pressure, high-temperature vapor.
5. What does BTU measure?
A. Electrical resistance
B. Heat energy
C. Air velocity
D. Refrigerant pressure
Answer: B
Rationale: A British Thermal Unit (BTU) is a unit of heat energy
required to raise the temperature of one pound of water by one
degree Fahrenheit.
6. Which refrigerant safety classification indicates lower toxicity and
no flame propagation?
A. A1
B. B2
, C. A3
D. B1
Answer: A
Rationale: A1 refrigerants are lower toxicity and non-flammable
according to ASHRAE standards.
7. What is the purpose of a thermostat in an HVAC system?
A. Increase refrigerant pressure
B. Control system temperature by regulating operation
C. Filter air
D. Measure humidity only
Answer: B
Rationale: A thermostat senses temperature and signals HVAC
equipment to start or stop to maintain set conditions.
8. What is superheat?
A. Heat added after condensation
B. Temperature rise of refrigerant vapor above its boiling point
C. Heat lost in the condenser
D. Pressure drop in evaporator
and Correct Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant Download Pdf
1. What is the primary purpose of a refrigerant in an HVAC system?
A. Increase electrical efficiency
B. Absorb and release heat during phase changes
C. Lubricate compressor components
D. Filter airborne particles
Answer: B
Rationale: Refrigerant is designed to absorb heat at low
pressure/temperature during evaporation and release heat at high
pressure/temperature during condensation, enabling heat transfer
within the system.
2. Which law governs the relationship between pressure and volume
at constant temperature?
A. Boyle’s Law
B. Charles’s Law
,C. Ohm’s Law
D. Dalton’s Law
Answer: A
Rationale: Boyle’s Law states that pressure and volume are inversely
proportional when temperature remains constant.
3. What component removes moisture and contaminants from
refrigerant?
A. Accumulator
B. Expansion valve
C. Filter drier
D. Compressor
Answer: C
Rationale: A filter drier removes moisture, acids, and debris from the
refrigerant to protect system components.
4. What is the function of the compressor in a refrigeration system?
A. Reduce refrigerant temperature
B. Increase refrigerant pressure and temperature
,C. Store refrigerant
D. Measure airflow
Answer: B
Rationale: The compressor compresses low-pressure refrigerant vapor
into high-pressure, high-temperature vapor.
5. What does BTU measure?
A. Electrical resistance
B. Heat energy
C. Air velocity
D. Refrigerant pressure
Answer: B
Rationale: A British Thermal Unit (BTU) is a unit of heat energy
required to raise the temperature of one pound of water by one
degree Fahrenheit.
6. Which refrigerant safety classification indicates lower toxicity and
no flame propagation?
A. A1
B. B2
, C. A3
D. B1
Answer: A
Rationale: A1 refrigerants are lower toxicity and non-flammable
according to ASHRAE standards.
7. What is the purpose of a thermostat in an HVAC system?
A. Increase refrigerant pressure
B. Control system temperature by regulating operation
C. Filter air
D. Measure humidity only
Answer: B
Rationale: A thermostat senses temperature and signals HVAC
equipment to start or stop to maintain set conditions.
8. What is superheat?
A. Heat added after condensation
B. Temperature rise of refrigerant vapor above its boiling point
C. Heat lost in the condenser
D. Pressure drop in evaporator
