CO Refrigeration 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?
A. To increase the temperature of a space
B. To remove heat from a space or substance
C. To generate electrical power
D. To increase humidity
Answer: B. To remove heat from a space or substance
Rationale: Refrigeration systems operate by transferring heat from a
low-temperature area to a higher-temperature area. The refrigeration
cycle absorbs heat from the refrigerated space through the
evaporator and rejects that heat through the condenser.
, 2. Which component of a vapor-compression refrigeration system
absorbs heat from the refrigerated space?
A. Condenser
B. Compressor
C. Evaporator
D. Receiver
Answer: C. Evaporator
Rationale: The evaporator is the heat-absorbing component.
Refrigerant entering the evaporator at low pressure and temperature
absorbs heat from the surrounding air, product, or fluid and
evaporates.
3. What is the primary function of the compressor?
A. Remove moisture from refrigerant
B. Raise the pressure and temperature of refrigerant vapor
C. Reduce liquid refrigerant pressure
D. Store excess refrigerant
Answer: B. Raise the pressure and temperature of refrigerant vapor
Rationale: The compressor takes low-pressure refrigerant vapor from
the evaporator and compresses it into a high-pressure, high-
,temperature vapor. This allows the refrigerant to reject heat in the
condenser.
4. What happens to refrigerant pressure as it passes through a
typical expansion device?
A. It increases substantially
B. It remains constant
C. It decreases substantially
D. It becomes atmospheric pressure
Answer: C. It decreases substantially
Rationale: The expansion device creates a pressure drop between the
high-pressure and low-pressure sides of the refrigeration system. This
pressure reduction causes part of the liquid refrigerant to flash into
vapor and lowers its temperature.
5. Which component rejects heat from the refrigerant to the
surrounding environment?
A. Evaporator
B. Condenser
C. Accumulator
D. Expansion valve
Answer: B. Condenser
, Rationale: The condenser receives hot, high-pressure refrigerant vapor
from the compressor. Heat is removed from the refrigerant, causing it
to condense into a high-pressure liquid.
6. What is superheat?
A. The temperature of a liquid below its freezing point
B. The temperature of a vapor above its saturation temperature
C. The temperature difference between the compressor and condenser
D. The pressure difference between suction and discharge
Answer: B. The temperature of a vapor above its saturation
temperature
Rationale: Superheat represents how much a vapor's actual
temperature exceeds its saturation temperature at a given pressure.
Measuring evaporator outlet superheat is important for ensuring that
liquid refrigerant does not return to the compressor.
7. What is subcooling?
A. Cooling a vapor below its saturation temperature
B. Heating liquid refrigerant above its boiling temperature
C. Cooling a liquid below its saturation temperature
D. Reducing compressor discharge pressure
Answer: C. Cooling a liquid below its saturation temperature
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 increase the temperature of a space
B. To remove heat from a space or substance
C. To generate electrical power
D. To increase humidity
Answer: B. To remove heat from a space or substance
Rationale: Refrigeration systems operate by transferring heat from a
low-temperature area to a higher-temperature area. The refrigeration
cycle absorbs heat from the refrigerated space through the
evaporator and rejects that heat through the condenser.
, 2. Which component of a vapor-compression refrigeration system
absorbs heat from the refrigerated space?
A. Condenser
B. Compressor
C. Evaporator
D. Receiver
Answer: C. Evaporator
Rationale: The evaporator is the heat-absorbing component.
Refrigerant entering the evaporator at low pressure and temperature
absorbs heat from the surrounding air, product, or fluid and
evaporates.
3. What is the primary function of the compressor?
A. Remove moisture from refrigerant
B. Raise the pressure and temperature of refrigerant vapor
C. Reduce liquid refrigerant pressure
D. Store excess refrigerant
Answer: B. Raise the pressure and temperature of refrigerant vapor
Rationale: The compressor takes low-pressure refrigerant vapor from
the evaporator and compresses it into a high-pressure, high-
,temperature vapor. This allows the refrigerant to reject heat in the
condenser.
4. What happens to refrigerant pressure as it passes through a
typical expansion device?
A. It increases substantially
B. It remains constant
C. It decreases substantially
D. It becomes atmospheric pressure
Answer: C. It decreases substantially
Rationale: The expansion device creates a pressure drop between the
high-pressure and low-pressure sides of the refrigeration system. This
pressure reduction causes part of the liquid refrigerant to flash into
vapor and lowers its temperature.
5. Which component rejects heat from the refrigerant to the
surrounding environment?
A. Evaporator
B. Condenser
C. Accumulator
D. Expansion valve
Answer: B. Condenser
, Rationale: The condenser receives hot, high-pressure refrigerant vapor
from the compressor. Heat is removed from the refrigerant, causing it
to condense into a high-pressure liquid.
6. What is superheat?
A. The temperature of a liquid below its freezing point
B. The temperature of a vapor above its saturation temperature
C. The temperature difference between the compressor and condenser
D. The pressure difference between suction and discharge
Answer: B. The temperature of a vapor above its saturation
temperature
Rationale: Superheat represents how much a vapor's actual
temperature exceeds its saturation temperature at a given pressure.
Measuring evaporator outlet superheat is important for ensuring that
liquid refrigerant does not return to the compressor.
7. What is subcooling?
A. Cooling a vapor below its saturation temperature
B. Heating liquid refrigerant above its boiling temperature
C. Cooling a liquid below its saturation temperature
D. Reducing compressor discharge pressure
Answer: C. Cooling a liquid below its saturation temperature
