Texas HVAC Technician Examination
Questions And Correct Answers
(Verified Answers) Plus Rationales
2026 Q&A | Instant Download Pdf
1.
What is the primary purpose of the evaporator coil in a vapor-
compression air-conditioning system?
A. Reject heat to outdoor air
B. Compress refrigerant vapor
C. Absorb heat from the conditioned space
D. Meter refrigerant into the condenser
Answer: C. Absorb heat from the conditioned space
Rationale: The evaporator is the component where low-pressure
refrigerant absorbs heat from indoor air or another load. The
refrigerant boils as it absorbs heat, producing the cooling effect. The
condenser rejects heat, the compressor raises vapor pressure, and the
metering device controls refrigerant flow.
2.
Which component raises low-pressure refrigerant vapor to a higher
pressure and temperature?
A. Evaporator
B. Compressor
C. Receiver
D. Filter-drier
,Answer: B. Compressor
Rationale: The compressor takes low-pressure vapor from the
evaporator and compresses it into high-pressure, high-temperature
vapor. This prepares the refrigerant for heat rejection in the
condenser. Compressors do not normally pump liquid refrigerant
through the system.
3.
What is the primary function of the condenser?
A. Absorb indoor heat
B. Meter refrigerant
C. Reject heat from the refrigerant
D. Increase evaporator pressure
Answer: C. Reject heat from the refrigerant
Rationale: The condenser removes heat from the refrigerant and
transfers it to outdoor air, water, or another heat sink. During normal
operation, high-pressure refrigerant vapor condenses into high-
pressure liquid as heat is rejected.
4.
What is the primary purpose of a thermostatic expansion valve?
A. Increase compressor speed
B. Control refrigerant flow into the evaporator
C. Remove moisture from oil
D. Raise condensing pressure
Answer: B. Control refrigerant flow into the evaporator
Rationale: A thermostatic expansion valve meters refrigerant into the
evaporator according to evaporator load and superheat conditions.
,Proper metering helps maintain adequate evaporator performance
while protecting the compressor from excessive liquid return.
5.
What does superheat describe?
A. Temperature below saturation
B. Temperature of a liquid below freezing
C. Temperature of vapor above its saturation temperature
D. Pressure above design pressure
Answer: C. Temperature of vapor above its saturation temperature
Rationale: Superheat is the amount by which vapor temperature
exceeds its saturation temperature at a given pressure. In air-
conditioning service, suction superheat helps determine whether
refrigerant is properly evaporating and whether liquid refrigerant is
being kept out of the compressor.
6.
What does subcooling describe?
A. Liquid temperature below its saturation temperature
B. Vapor temperature above saturation
C. Compressor discharge temperature
D. Condenser pressure above design
Answer: A. Liquid temperature below its saturation temperature
Rationale: Subcooling occurs when liquid refrigerant is cooled below
its saturation temperature at the corresponding pressure. Proper liquid
subcooling can help ensure that solid liquid refrigerant reaches the
metering device without excessive flash gas in the liquid line.
7.
, Which refrigerant state normally enters a typical air-conditioning
compressor?
A. High-pressure liquid
B. Low-pressure vapor
C. High-pressure mixture
D. Low-pressure liquid
Answer: B. Low-pressure vapor
Rationale: A vapor-compression compressor is designed to compress
vapor. Liquid entering the compressor can cause severe mechanical
damage, commonly referred to as liquid slugging. Proper system
operation therefore requires adequate evaporation and appropriate
superheat.
8.
What is the main purpose of a liquid-line filter-drier?
A. Increase airflow
B. Remove moisture and contaminants
C. Increase compressor capacity
D. Reduce condenser airflow
Answer: B. Remove moisture and contaminants
Rationale: A filter-drier removes moisture, acids, dirt, and other
contaminants from the refrigerant circuit. Moisture can react with
refrigerant and oil to form acids or freeze at restrictions, making
filtration and drying important after system contamination or service.
9.
What instrument is commonly used to measure refrigerant pressure?
Questions And Correct Answers
(Verified Answers) Plus Rationales
2026 Q&A | Instant Download Pdf
1.
What is the primary purpose of the evaporator coil in a vapor-
compression air-conditioning system?
A. Reject heat to outdoor air
B. Compress refrigerant vapor
C. Absorb heat from the conditioned space
D. Meter refrigerant into the condenser
Answer: C. Absorb heat from the conditioned space
Rationale: The evaporator is the component where low-pressure
refrigerant absorbs heat from indoor air or another load. The
refrigerant boils as it absorbs heat, producing the cooling effect. The
condenser rejects heat, the compressor raises vapor pressure, and the
metering device controls refrigerant flow.
2.
Which component raises low-pressure refrigerant vapor to a higher
pressure and temperature?
A. Evaporator
B. Compressor
C. Receiver
D. Filter-drier
,Answer: B. Compressor
Rationale: The compressor takes low-pressure vapor from the
evaporator and compresses it into high-pressure, high-temperature
vapor. This prepares the refrigerant for heat rejection in the
condenser. Compressors do not normally pump liquid refrigerant
through the system.
3.
What is the primary function of the condenser?
A. Absorb indoor heat
B. Meter refrigerant
C. Reject heat from the refrigerant
D. Increase evaporator pressure
Answer: C. Reject heat from the refrigerant
Rationale: The condenser removes heat from the refrigerant and
transfers it to outdoor air, water, or another heat sink. During normal
operation, high-pressure refrigerant vapor condenses into high-
pressure liquid as heat is rejected.
4.
What is the primary purpose of a thermostatic expansion valve?
A. Increase compressor speed
B. Control refrigerant flow into the evaporator
C. Remove moisture from oil
D. Raise condensing pressure
Answer: B. Control refrigerant flow into the evaporator
Rationale: A thermostatic expansion valve meters refrigerant into the
evaporator according to evaporator load and superheat conditions.
,Proper metering helps maintain adequate evaporator performance
while protecting the compressor from excessive liquid return.
5.
What does superheat describe?
A. Temperature below saturation
B. Temperature of a liquid below freezing
C. Temperature of vapor above its saturation temperature
D. Pressure above design pressure
Answer: C. Temperature of vapor above its saturation temperature
Rationale: Superheat is the amount by which vapor temperature
exceeds its saturation temperature at a given pressure. In air-
conditioning service, suction superheat helps determine whether
refrigerant is properly evaporating and whether liquid refrigerant is
being kept out of the compressor.
6.
What does subcooling describe?
A. Liquid temperature below its saturation temperature
B. Vapor temperature above saturation
C. Compressor discharge temperature
D. Condenser pressure above design
Answer: A. Liquid temperature below its saturation temperature
Rationale: Subcooling occurs when liquid refrigerant is cooled below
its saturation temperature at the corresponding pressure. Proper liquid
subcooling can help ensure that solid liquid refrigerant reaches the
metering device without excessive flash gas in the liquid line.
7.
, Which refrigerant state normally enters a typical air-conditioning
compressor?
A. High-pressure liquid
B. Low-pressure vapor
C. High-pressure mixture
D. Low-pressure liquid
Answer: B. Low-pressure vapor
Rationale: A vapor-compression compressor is designed to compress
vapor. Liquid entering the compressor can cause severe mechanical
damage, commonly referred to as liquid slugging. Proper system
operation therefore requires adequate evaporation and appropriate
superheat.
8.
What is the main purpose of a liquid-line filter-drier?
A. Increase airflow
B. Remove moisture and contaminants
C. Increase compressor capacity
D. Reduce condenser airflow
Answer: B. Remove moisture and contaminants
Rationale: A filter-drier removes moisture, acids, dirt, and other
contaminants from the refrigerant circuit. Moisture can react with
refrigerant and oil to form acids or freeze at restrictions, making
filtration and drying important after system contamination or service.
9.
What instrument is commonly used to measure refrigerant pressure?
