AL REF Refrigeration Contractor
Exam Questions And Correct Answers
(Verified Answers) Plus Rationale2026
Q&A| Instant Download Pdf
1. What is the primary purpose of a refrigeration system?
A. To heat a space
B. To remove moisture
C. To remove heat from a space or substance
D. To circulate air
Rationale: The main function of a refrigeration system is to extract
heat from a space or substance to lower its temperature.
2. Which component of a refrigeration system compresses the refrigerant?
A. Evaporator
B. Expansion valve
C. Compressor
D. Condenser
Rationale: The compressor is responsible for compressing the
refrigerant, raising its pressure and temperature.
3. What is the purpose of the condenser in a refrigeration system?
A. To evaporate refrigerant
B. To reject heat to the surroundings
C. To increase refrigerant pressure
D. To filter the refrigerant
Rationale: The condenser removes heat from the high-pressure
refrigerant and releases it to the environment.
4. Which type of refrigerant is commonly used in commercial
refrigeration?
A. R-22
B. R-134a
C. R-12
, D. R-717
Rationale: R-134a is widely used in commercial refrigeration systems
due to its safety and efficiency properties.
5. What device regulates the flow of refrigerant into the evaporator?
A. Compressor
B. Condenser
C. Expansion valve
D. Receiver
Rationale: The expansion valve meters refrigerant flow to maintain
proper pressure and temperature in the evaporator.
6. What is the typical function of an evaporator in a refrigeration system?
A. To compress refrigerant
B. To absorb heat from the space or substance
C. To reject heat to the atmosphere
D. To circulate refrigerant
Rationale: The evaporator absorbs heat from the environment,
causing the refrigerant to evaporate.
7. In a vapor-compression refrigeration cycle, what is the state of
refrigerant entering the compressor?
A. High-pressure gas
B. Low-pressure gas
C. High-pressure liquid
D. Low-pressure liquid
Rationale: Refrigerant enters the compressor as a low-pressure vapor
from the evaporator.
8. What safety device protects a refrigeration system from overpressure?
A. Thermostat
B. Expansion valve
C. Pressure relief valve
D. Filter drier
Rationale: A pressure relief valve prevents dangerous overpressure in
the system.
9. Which of the following is a common cause of compressor failure?
A. Evaporator freezing
B. Lubrication failure
C. Condenser cleaning
D. Expansion valve adjustment
, Rationale: Lack of lubrication can cause excessive wear and
overheating, leading to compressor failure.
10. What is superheating in a refrigeration system?
A. Heat removed in the condenser
B. Refrigerant subcooling
C. Temperature increase of vapor above its saturation point
D. Expansion of liquid refrigerant
Rationale: Superheating refers to heating the refrigerant vapor above
its boiling temperature before entering the compressor.
11. Subcooling refrigerant increases system efficiency by:
A. Reducing condenser load
B. Ensuring only liquid refrigerant enters the expansion device
C. Cooling the evaporator
D. Reducing compressor pressure
Rationale: Subcooling ensures the expansion device receives fully
liquid refrigerant, improving efficiency.
12. Which type of compressor uses pistons to compress refrigerant?
A. Scroll
B. Centrifugal
C. Reciprocating
D. Screw
Rationale: Reciprocating compressors use pistons and cylinders to
compress refrigerant.
13. What is the effect of air in a refrigeration system?
A. Reduces efficiency and increases pressure
B. Enhances cooling
C. Lubricates the compressor
D. Reduces system noise
Rationale: Air in the system reduces heat transfer efficiency and can
increase pressure, causing operational problems.
14. Which of the following is an example of an environmentally
friendly refrigerant?
A. R-22
B. R-290 (Propane)
C. R-12
D. R-502
Exam Questions And Correct Answers
(Verified Answers) Plus Rationale2026
Q&A| Instant Download Pdf
1. What is the primary purpose of a refrigeration system?
A. To heat a space
B. To remove moisture
C. To remove heat from a space or substance
D. To circulate air
Rationale: The main function of a refrigeration system is to extract
heat from a space or substance to lower its temperature.
2. Which component of a refrigeration system compresses the refrigerant?
A. Evaporator
B. Expansion valve
C. Compressor
D. Condenser
Rationale: The compressor is responsible for compressing the
refrigerant, raising its pressure and temperature.
3. What is the purpose of the condenser in a refrigeration system?
A. To evaporate refrigerant
B. To reject heat to the surroundings
C. To increase refrigerant pressure
D. To filter the refrigerant
Rationale: The condenser removes heat from the high-pressure
refrigerant and releases it to the environment.
4. Which type of refrigerant is commonly used in commercial
refrigeration?
A. R-22
B. R-134a
C. R-12
, D. R-717
Rationale: R-134a is widely used in commercial refrigeration systems
due to its safety and efficiency properties.
5. What device regulates the flow of refrigerant into the evaporator?
A. Compressor
B. Condenser
C. Expansion valve
D. Receiver
Rationale: The expansion valve meters refrigerant flow to maintain
proper pressure and temperature in the evaporator.
6. What is the typical function of an evaporator in a refrigeration system?
A. To compress refrigerant
B. To absorb heat from the space or substance
C. To reject heat to the atmosphere
D. To circulate refrigerant
Rationale: The evaporator absorbs heat from the environment,
causing the refrigerant to evaporate.
7. In a vapor-compression refrigeration cycle, what is the state of
refrigerant entering the compressor?
A. High-pressure gas
B. Low-pressure gas
C. High-pressure liquid
D. Low-pressure liquid
Rationale: Refrigerant enters the compressor as a low-pressure vapor
from the evaporator.
8. What safety device protects a refrigeration system from overpressure?
A. Thermostat
B. Expansion valve
C. Pressure relief valve
D. Filter drier
Rationale: A pressure relief valve prevents dangerous overpressure in
the system.
9. Which of the following is a common cause of compressor failure?
A. Evaporator freezing
B. Lubrication failure
C. Condenser cleaning
D. Expansion valve adjustment
, Rationale: Lack of lubrication can cause excessive wear and
overheating, leading to compressor failure.
10. What is superheating in a refrigeration system?
A. Heat removed in the condenser
B. Refrigerant subcooling
C. Temperature increase of vapor above its saturation point
D. Expansion of liquid refrigerant
Rationale: Superheating refers to heating the refrigerant vapor above
its boiling temperature before entering the compressor.
11. Subcooling refrigerant increases system efficiency by:
A. Reducing condenser load
B. Ensuring only liquid refrigerant enters the expansion device
C. Cooling the evaporator
D. Reducing compressor pressure
Rationale: Subcooling ensures the expansion device receives fully
liquid refrigerant, improving efficiency.
12. Which type of compressor uses pistons to compress refrigerant?
A. Scroll
B. Centrifugal
C. Reciprocating
D. Screw
Rationale: Reciprocating compressors use pistons and cylinders to
compress refrigerant.
13. What is the effect of air in a refrigeration system?
A. Reduces efficiency and increases pressure
B. Enhances cooling
C. Lubricates the compressor
D. Reduces system noise
Rationale: Air in the system reduces heat transfer efficiency and can
increase pressure, causing operational problems.
14. Which of the following is an example of an environmentally
friendly refrigerant?
A. R-22
B. R-290 (Propane)
C. R-12
D. R-502
