AL HVAC Heating, Ventilation & Air
Conditioning Contractor Exam Questions and
Correct Answers (Verified Answers) Plus
Rationale 2027 Q&A| Instant Download Pdf
1. What is the primary purpose of a refrigeration system in an HVAC
application?
a. To create heat from electrical resistance
b. To remove heat from a space or substance
c. To increase indoor humidity
d. To increase atmospheric pressure
Answer: b. To remove heat from a space or substance
Rationale: A refrigeration system transfers heat from a cooler location
to a warmer location. In air conditioning, the system removes heat from
indoor air and rejects that heat outdoors. The refrigeration cycle does
not destroy heat; it moves it using a refrigerant and mechanical
components.
, 2. Which component of a vapor-compression refrigeration system
raises the pressure and temperature 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 prepares the refrigerant for heat rejection in
the condenser.
3. What is the main function of the evaporator coil in an air-
conditioning system?
a. Reject heat to outdoor air
b. Absorb heat from indoor air
c. Increase refrigerant pressure
d. Store liquid refrigerant
Answer: b. Absorb heat from indoor air
Rationale: The evaporator is the indoor heat-absorbing component in a
conventional split air-conditioning system. Low-pressure refrigerant
,evaporates inside the coil while absorbing sensible and, when
applicable, latent heat from the air passing over it.
4. Which refrigerant condition normally enters the compressor in a
properly operating vapor-compression system?
a. High-pressure liquid
b. Low-pressure vapor
c. High-pressure liquid-vapor mixture
d. Atmospheric-pressure liquid
Answer: b. Low-pressure vapor
Rationale: The compressor is designed to receive vapor rather than
liquid. Liquid entering a reciprocating or scroll compressor can cause
serious mechanical damage, a condition commonly called liquid
slugging or flooding.
5. What is the primary purpose of the condenser?
a. Absorb heat from the conditioned space
b. Lower the refrigerant pressure
c. Reject heat from the refrigerant
d. Meter refrigerant into the evaporator
Answer: c. Reject heat from the refrigerant
, Rationale: The condenser removes heat from the high-pressure
refrigerant vapor after compression. As heat is rejected, the refrigerant
changes from vapor to liquid, making it ready for the metering device.
6. Which device is commonly used to meter refrigerant into an
evaporator?
a. Contactor
b. Expansion valve
c. Filter-drier
d. Accumulator
Answer: b. Expansion valve
Rationale: An expansion device controls the flow of refrigerant entering
the evaporator and creates a pressure drop. This pressure reduction
allows the refrigerant to evaporate at the lower temperature required
for heat absorption.
7. What happens to refrigerant pressure as it passes through a
typical expansion device?
a. It increases substantially
b. It remains exactly constant
c. It decreases substantially
d. It becomes atmospheric pressure
Conditioning Contractor Exam Questions and
Correct Answers (Verified Answers) Plus
Rationale 2027 Q&A| Instant Download Pdf
1. What is the primary purpose of a refrigeration system in an HVAC
application?
a. To create heat from electrical resistance
b. To remove heat from a space or substance
c. To increase indoor humidity
d. To increase atmospheric pressure
Answer: b. To remove heat from a space or substance
Rationale: A refrigeration system transfers heat from a cooler location
to a warmer location. In air conditioning, the system removes heat from
indoor air and rejects that heat outdoors. The refrigeration cycle does
not destroy heat; it moves it using a refrigerant and mechanical
components.
, 2. Which component of a vapor-compression refrigeration system
raises the pressure and temperature 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 prepares the refrigerant for heat rejection in
the condenser.
3. What is the main function of the evaporator coil in an air-
conditioning system?
a. Reject heat to outdoor air
b. Absorb heat from indoor air
c. Increase refrigerant pressure
d. Store liquid refrigerant
Answer: b. Absorb heat from indoor air
Rationale: The evaporator is the indoor heat-absorbing component in a
conventional split air-conditioning system. Low-pressure refrigerant
,evaporates inside the coil while absorbing sensible and, when
applicable, latent heat from the air passing over it.
4. Which refrigerant condition normally enters the compressor in a
properly operating vapor-compression system?
a. High-pressure liquid
b. Low-pressure vapor
c. High-pressure liquid-vapor mixture
d. Atmospheric-pressure liquid
Answer: b. Low-pressure vapor
Rationale: The compressor is designed to receive vapor rather than
liquid. Liquid entering a reciprocating or scroll compressor can cause
serious mechanical damage, a condition commonly called liquid
slugging or flooding.
5. What is the primary purpose of the condenser?
a. Absorb heat from the conditioned space
b. Lower the refrigerant pressure
c. Reject heat from the refrigerant
d. Meter refrigerant into the evaporator
Answer: c. Reject heat from the refrigerant
, Rationale: The condenser removes heat from the high-pressure
refrigerant vapor after compression. As heat is rejected, the refrigerant
changes from vapor to liquid, making it ready for the metering device.
6. Which device is commonly used to meter refrigerant into an
evaporator?
a. Contactor
b. Expansion valve
c. Filter-drier
d. Accumulator
Answer: b. Expansion valve
Rationale: An expansion device controls the flow of refrigerant entering
the evaporator and creates a pressure drop. This pressure reduction
allows the refrigerant to evaporate at the lower temperature required
for heat absorption.
7. What happens to refrigerant pressure as it passes through a
typical expansion device?
a. It increases substantially
b. It remains exactly constant
c. It decreases substantially
d. It becomes atmospheric pressure
