Oklahoma HVAC/R Assessment Exam
Practice Questions And Correct
Answers (Verified Answers) Plus
Rationale 2027 Q&A| Instant
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1. In a vapor-compression refrigeration system, what is the primary
function of the compressor?
A. Remove moisture from the refrigerant
B. Reduce the refrigerant pressure before the evaporator
C. Raise the refrigerant pressure and temperature and circulate it
through the system
D. Convert liquid refrigerant directly into subcooled liquid
The compressor raises the pressure and temperature of the refrigerant
vapor while providing the pressure difference necessary to circulate
refrigerant through the refrigeration cycle.
2. Which component is primarily responsible for rejecting heat from
the refrigerant to the surrounding environment?
,A. Evaporator
B. Condenser
C. Expansion valve
D. Accumulator
The condenser removes heat from the high-pressure refrigerant vapor,
causing it to condense into a high-pressure liquid.
3. What is the principal function of an evaporator in a refrigeration
system?
A. Increase condensing pressure
B. Store compressor oil
C. Absorb heat from the conditioned space or medium
D. Remove noncondensable gases
The evaporator absorbs heat as refrigerant changes from a low-pressure
liquid-vapor mixture into vapor.
4. What happens to refrigerant pressure as it passes through a
properly operating thermostatic expansion valve?
A. It increases substantially
B. It decreases substantially
C. It remains exactly constant
D. It increases only when superheat decreases
,The expansion device creates a pressure drop that changes the
refrigerant from a high-pressure liquid into a low-pressure mixture
entering the evaporator.
5. Which measurement is most directly used to determine evaporator
superheat?
A. Condenser outlet temperature minus outdoor temperature
B. Liquid-line temperature minus saturation temperature
C. Actual suction-line temperature minus evaporator saturation
temperature
D. Discharge temperature minus condensing temperature
Superheat is calculated by subtracting the refrigerant's saturation
temperature at the evaporator pressure from the actual vapor
temperature at the measurement point.
6. A system has a suction pressure corresponding to a saturation
temperature of 40°F and a suction-line temperature of 50°F at the
same location. What is the superheat?
A. 5°F
B. 10°F
C. 40°F
D. 90°F
Superheat equals actual vapor temperature minus saturation
temperature, so 50°F − 40°F = 10°F.
, 7. What does subcooling represent in a refrigeration system?
A. Temperature of vapor above its boiling point
B. Temperature of liquid below its saturation temperature at a given
pressure
C. Temperature of compressor oil below ambient temperature
D. Temperature difference between return and supply air
Subcooling indicates how far a liquid refrigerant has been cooled below
its saturation temperature at the measured pressure.
8. A condenser outlet has a saturation temperature of 100°F and an
actual liquid temperature of 90°F. What is the indicated subcooling?
A. 5°F
B. 10°F
C. 90°F
D. 190°F
Subcooling is calculated as saturation temperature minus actual liquid
temperature, giving 100°F − 90°F = 10°F.
9. What is the primary purpose of a filter-drier installed in a
refrigeration system?
A. Increase compressor capacity
B. Raise suction pressure
C. Remove moisture, acids, and particulate contaminants from the
Practice Questions And Correct
Answers (Verified Answers) Plus
Rationale 2027 Q&A| Instant
Download Pdf.
1. In a vapor-compression refrigeration system, what is the primary
function of the compressor?
A. Remove moisture from the refrigerant
B. Reduce the refrigerant pressure before the evaporator
C. Raise the refrigerant pressure and temperature and circulate it
through the system
D. Convert liquid refrigerant directly into subcooled liquid
The compressor raises the pressure and temperature of the refrigerant
vapor while providing the pressure difference necessary to circulate
refrigerant through the refrigeration cycle.
2. Which component is primarily responsible for rejecting heat from
the refrigerant to the surrounding environment?
,A. Evaporator
B. Condenser
C. Expansion valve
D. Accumulator
The condenser removes heat from the high-pressure refrigerant vapor,
causing it to condense into a high-pressure liquid.
3. What is the principal function of an evaporator in a refrigeration
system?
A. Increase condensing pressure
B. Store compressor oil
C. Absorb heat from the conditioned space or medium
D. Remove noncondensable gases
The evaporator absorbs heat as refrigerant changes from a low-pressure
liquid-vapor mixture into vapor.
4. What happens to refrigerant pressure as it passes through a
properly operating thermostatic expansion valve?
A. It increases substantially
B. It decreases substantially
C. It remains exactly constant
D. It increases only when superheat decreases
,The expansion device creates a pressure drop that changes the
refrigerant from a high-pressure liquid into a low-pressure mixture
entering the evaporator.
5. Which measurement is most directly used to determine evaporator
superheat?
A. Condenser outlet temperature minus outdoor temperature
B. Liquid-line temperature minus saturation temperature
C. Actual suction-line temperature minus evaporator saturation
temperature
D. Discharge temperature minus condensing temperature
Superheat is calculated by subtracting the refrigerant's saturation
temperature at the evaporator pressure from the actual vapor
temperature at the measurement point.
6. A system has a suction pressure corresponding to a saturation
temperature of 40°F and a suction-line temperature of 50°F at the
same location. What is the superheat?
A. 5°F
B. 10°F
C. 40°F
D. 90°F
Superheat equals actual vapor temperature minus saturation
temperature, so 50°F − 40°F = 10°F.
, 7. What does subcooling represent in a refrigeration system?
A. Temperature of vapor above its boiling point
B. Temperature of liquid below its saturation temperature at a given
pressure
C. Temperature of compressor oil below ambient temperature
D. Temperature difference between return and supply air
Subcooling indicates how far a liquid refrigerant has been cooled below
its saturation temperature at the measured pressure.
8. A condenser outlet has a saturation temperature of 100°F and an
actual liquid temperature of 90°F. What is the indicated subcooling?
A. 5°F
B. 10°F
C. 90°F
D. 190°F
Subcooling is calculated as saturation temperature minus actual liquid
temperature, giving 100°F − 90°F = 10°F.
9. What is the primary purpose of a filter-drier installed in a
refrigeration system?
A. Increase compressor capacity
B. Raise suction pressure
C. Remove moisture, acids, and particulate contaminants from the
