North Carolina Refrigeration Contractors Board –
Refrigeration Contractor Examination (Class A)
Questions and Correct Answers (Verified Answers)
Plus Rationale 2027 Q&A| Instant Download Pdf
1. What is the primary purpose of a refrigeration system?
A. To create coldness directly
B. To transfer heat from a lower-temperature space to a higher-
temperature location
C. To increase the humidity of a conditioned space
D. To convert electrical energy directly into cooling energy
Answer: B. To transfer heat from a lower-temperature space to a
higher-temperature location
Rationale: A refrigeration system does not actually create “cold.” It
removes heat from the refrigerated space and rejects that heat to
another location, normally the surrounding air or cooling water. The
refrigeration cycle accomplishes this through the coordinated
operation of the compressor, condenser, metering device, and
evaporator.
, 2. Which component is responsible for compressing low-pressure
refrigerant vapor and raising its pressure and temperature?
A. Evaporator
B. Condenser
C. Compressor
D. Expansion valve
Answer: C. Compressor
Rationale: The compressor receives low-pressure vapor from the
evaporator and compresses it into a high-pressure, high-temperature
vapor. This pressure increase allows the refrigerant to reject heat in
the condenser. Compressors are therefore the driving force that
maintains refrigerant circulation through the system.
3. In a conventional vapor-compression refrigeration cycle, which
component follows the condenser?
A. Compressor
B. Metering device
C. Evaporator fan
D. Accumulator
Answer: B. Metering device
,Rationale: After refrigerant condenses into a high-pressure liquid in
the condenser, it flows through a metering device such as a
thermostatic expansion valve or electronic expansion valve. The
device reduces refrigerant pressure and controls its flow into the
evaporator.
4. What occurs to the refrigerant as it passes through a properly
operating expansion device?
A. Its pressure increases substantially
B. Its temperature and pressure decrease
C. It becomes a high-pressure superheated vapor
D. It releases all of its heat to the condenser
Answer: B. Its temperature and pressure decrease
Rationale: The metering device creates a pressure drop between the
high side and low side of the refrigeration system. Some liquid flashes
into vapor during this process, lowering the refrigerant temperature
so that it can absorb heat in the evaporator.
5. What is the primary function of the evaporator?
A. Reject heat to outdoor air
B. Compress refrigerant vapor
, C. Absorb heat from the refrigerated space or load
D. Store liquid refrigerant permanently
Answer: C. Absorb heat from the refrigerated space or load
Rationale: Low-pressure refrigerant enters the evaporator and
absorbs heat from the surrounding air, product, water, or another
medium. As heat is absorbed, the refrigerant boils or evaporates,
changing from a predominantly liquid mixture into vapor.
6. What is superheat?
A. The temperature of liquid below its saturation temperature
B. The temperature difference between a vapor's actual temperature
and its saturation temperature at the same pressure
C. The pressure difference between the suction and discharge sides
D. The temperature difference across a condenser
Answer: B. The temperature difference between a vapor's actual
temperature and its saturation temperature at the same pressure
Rationale: Superheat indicates how much a vapor has been heated
above its saturation temperature. In refrigeration service, suction
superheat is particularly important because adequate superheat helps
ensure that liquid refrigerant does not return to the compressor.
7. What is subcooling?
Refrigeration Contractor Examination (Class A)
Questions and Correct Answers (Verified Answers)
Plus Rationale 2027 Q&A| Instant Download Pdf
1. What is the primary purpose of a refrigeration system?
A. To create coldness directly
B. To transfer heat from a lower-temperature space to a higher-
temperature location
C. To increase the humidity of a conditioned space
D. To convert electrical energy directly into cooling energy
Answer: B. To transfer heat from a lower-temperature space to a
higher-temperature location
Rationale: A refrigeration system does not actually create “cold.” It
removes heat from the refrigerated space and rejects that heat to
another location, normally the surrounding air or cooling water. The
refrigeration cycle accomplishes this through the coordinated
operation of the compressor, condenser, metering device, and
evaporator.
, 2. Which component is responsible for compressing low-pressure
refrigerant vapor and raising its pressure and temperature?
A. Evaporator
B. Condenser
C. Compressor
D. Expansion valve
Answer: C. Compressor
Rationale: The compressor receives low-pressure vapor from the
evaporator and compresses it into a high-pressure, high-temperature
vapor. This pressure increase allows the refrigerant to reject heat in
the condenser. Compressors are therefore the driving force that
maintains refrigerant circulation through the system.
3. In a conventional vapor-compression refrigeration cycle, which
component follows the condenser?
A. Compressor
B. Metering device
C. Evaporator fan
D. Accumulator
Answer: B. Metering device
,Rationale: After refrigerant condenses into a high-pressure liquid in
the condenser, it flows through a metering device such as a
thermostatic expansion valve or electronic expansion valve. The
device reduces refrigerant pressure and controls its flow into the
evaporator.
4. What occurs to the refrigerant as it passes through a properly
operating expansion device?
A. Its pressure increases substantially
B. Its temperature and pressure decrease
C. It becomes a high-pressure superheated vapor
D. It releases all of its heat to the condenser
Answer: B. Its temperature and pressure decrease
Rationale: The metering device creates a pressure drop between the
high side and low side of the refrigeration system. Some liquid flashes
into vapor during this process, lowering the refrigerant temperature
so that it can absorb heat in the evaporator.
5. What is the primary function of the evaporator?
A. Reject heat to outdoor air
B. Compress refrigerant vapor
, C. Absorb heat from the refrigerated space or load
D. Store liquid refrigerant permanently
Answer: C. Absorb heat from the refrigerated space or load
Rationale: Low-pressure refrigerant enters the evaporator and
absorbs heat from the surrounding air, product, water, or another
medium. As heat is absorbed, the refrigerant boils or evaporates,
changing from a predominantly liquid mixture into vapor.
6. What is superheat?
A. The temperature of liquid below its saturation temperature
B. The temperature difference between a vapor's actual temperature
and its saturation temperature at the same pressure
C. The pressure difference between the suction and discharge sides
D. The temperature difference across a condenser
Answer: B. The temperature difference between a vapor's actual
temperature and its saturation temperature at the same pressure
Rationale: Superheat indicates how much a vapor has been heated
above its saturation temperature. In refrigeration service, suction
superheat is particularly important because adequate superheat helps
ensure that liquid refrigerant does not return to the compressor.
7. What is subcooling?
