Ontario Refrigeration Operator Class B 2026/2027 Exam questions and
answers with rationales 2026/2027 version
1. What is the primary purpose of a refrigeration system?
A. To create cold from nothing
B. To transfer heat from a lower-temperature space to a higher-temperature sink
C. To increase the temperature of the refrigerated space
D. To eliminate all moisture from the air
Correct Answer: B
Rationale: Refrigeration removes heat from a low-temperature area and rejects it
to a higher-temperature environment.
2. In a basic vapour-compression refrigeration cycle, which component raises
the pressure of the refrigerant vapour?
A. Evaporator
B. Condenser
C. Compressor
D. Expansion valve
Correct Answer: C
Rationale: The compressor increases the pressure and temperature of the
refrigerant vapour.
3. What is the main function of the evaporator?
A. Reject heat to the atmosphere
B. Absorb heat from the refrigerated space
C. Increase refrigerant pressure
D. Store liquid refrigerant
Correct Answer: B
Rationale: Refrigerant absorbs heat as it evaporates in the evaporator.
4. What occurs in the condenser?
A. Refrigerant absorbs heat and evaporates
B. Refrigerant pressure is reduced
C. Refrigerant rejects heat and condenses
D. Refrigerant is compressed into a vacuum
,Correct Answer: C
Rationale: The condenser removes heat from high-pressure refrigerant vapour,
causing it to condense into liquid.
5. What is the primary function of an expansion valve?
A. Increase refrigerant pressure
B. Reduce refrigerant pressure and control flow
C. Remove oil from the compressor
D. Increase condenser temperature
Correct Answer: B
Rationale: The expansion device creates a pressure drop and meters refrigerant
into the evaporator.
6. Superheated vapour is refrigerant vapour that is:
A. Below its saturation temperature
B. At its freezing point
C. Above its saturation temperature at a given pressure
D. Mixed entirely with liquid
Correct Answer: C
Rationale: Superheated vapour has a temperature above the saturation temperature
corresponding to its pressure.
7. Subcooling refers to liquid refrigerant that is:
A. Above its boiling point
B. Below its saturation temperature
C. Completely vaporized
D. At compressor discharge temperature
Correct Answer: B
Rationale: Subcooled liquid is cooled below its saturation temperature at the
existing pressure.
8. What can excessive liquid refrigerant entering a compressor cause?
A. Improved lubrication
B. Liquid slugging and compressor damage
C. Lower condenser pressure only
D. Increased compressor efficiency
, Correct Answer: B
Rationale: Compressors are designed to compress vapour, not liquid. Liquid
slugging can cause serious mechanical damage.
9. What is the purpose of a receiver in a refrigeration system?
A. To store liquid refrigerant
B. To compress refrigerant vapour
C. To absorb heat from the room
D. To remove non-condensables
Correct Answer: A
Rationale: A receiver stores liquid refrigerant and helps manage system charge
during varying operating conditions.
10. What is the purpose of an oil separator?
A. To remove water from the condenser
B. To separate oil from discharge gas and return it to the compressor
C. To reduce evaporator pressure
D. To cool electrical wiring
Correct Answer: B
Rationale: Oil separators help prevent excessive oil circulation through the
refrigeration system.
11. What is the main purpose of a filter-drier?
A. To increase refrigerant pressure
B. To remove moisture and contaminants
C. To raise evaporator temperature
D. To increase compressor speed
Correct Answer: B
Rationale: Filter-driers remove moisture, acids, and particulate contamination
from the refrigerant system.
12. Why are non-condensable gases undesirable in a refrigeration system?
A. They improve heat transfer
B. They can increase condensing pressure and reduce efficiency
C. They reduce discharge pressure
D. They increase refrigerant purity
answers with rationales 2026/2027 version
1. What is the primary purpose of a refrigeration system?
A. To create cold from nothing
B. To transfer heat from a lower-temperature space to a higher-temperature sink
C. To increase the temperature of the refrigerated space
D. To eliminate all moisture from the air
Correct Answer: B
Rationale: Refrigeration removes heat from a low-temperature area and rejects it
to a higher-temperature environment.
2. In a basic vapour-compression refrigeration cycle, which component raises
the pressure of the refrigerant vapour?
A. Evaporator
B. Condenser
C. Compressor
D. Expansion valve
Correct Answer: C
Rationale: The compressor increases the pressure and temperature of the
refrigerant vapour.
3. What is the main function of the evaporator?
A. Reject heat to the atmosphere
B. Absorb heat from the refrigerated space
C. Increase refrigerant pressure
D. Store liquid refrigerant
Correct Answer: B
Rationale: Refrigerant absorbs heat as it evaporates in the evaporator.
4. What occurs in the condenser?
A. Refrigerant absorbs heat and evaporates
B. Refrigerant pressure is reduced
C. Refrigerant rejects heat and condenses
D. Refrigerant is compressed into a vacuum
,Correct Answer: C
Rationale: The condenser removes heat from high-pressure refrigerant vapour,
causing it to condense into liquid.
5. What is the primary function of an expansion valve?
A. Increase refrigerant pressure
B. Reduce refrigerant pressure and control flow
C. Remove oil from the compressor
D. Increase condenser temperature
Correct Answer: B
Rationale: The expansion device creates a pressure drop and meters refrigerant
into the evaporator.
6. Superheated vapour is refrigerant vapour that is:
A. Below its saturation temperature
B. At its freezing point
C. Above its saturation temperature at a given pressure
D. Mixed entirely with liquid
Correct Answer: C
Rationale: Superheated vapour has a temperature above the saturation temperature
corresponding to its pressure.
7. Subcooling refers to liquid refrigerant that is:
A. Above its boiling point
B. Below its saturation temperature
C. Completely vaporized
D. At compressor discharge temperature
Correct Answer: B
Rationale: Subcooled liquid is cooled below its saturation temperature at the
existing pressure.
8. What can excessive liquid refrigerant entering a compressor cause?
A. Improved lubrication
B. Liquid slugging and compressor damage
C. Lower condenser pressure only
D. Increased compressor efficiency
, Correct Answer: B
Rationale: Compressors are designed to compress vapour, not liquid. Liquid
slugging can cause serious mechanical damage.
9. What is the purpose of a receiver in a refrigeration system?
A. To store liquid refrigerant
B. To compress refrigerant vapour
C. To absorb heat from the room
D. To remove non-condensables
Correct Answer: A
Rationale: A receiver stores liquid refrigerant and helps manage system charge
during varying operating conditions.
10. What is the purpose of an oil separator?
A. To remove water from the condenser
B. To separate oil from discharge gas and return it to the compressor
C. To reduce evaporator pressure
D. To cool electrical wiring
Correct Answer: B
Rationale: Oil separators help prevent excessive oil circulation through the
refrigeration system.
11. What is the main purpose of a filter-drier?
A. To increase refrigerant pressure
B. To remove moisture and contaminants
C. To raise evaporator temperature
D. To increase compressor speed
Correct Answer: B
Rationale: Filter-driers remove moisture, acids, and particulate contamination
from the refrigerant system.
12. Why are non-condensable gases undesirable in a refrigeration system?
A. They improve heat transfer
B. They can increase condensing pressure and reduce efficiency
C. They reduce discharge pressure
D. They increase refrigerant purity
