Oklahoma HVAC/R Assessment Exam
Practice Questions And Correct
Answers (Verified Answers) Plus
Rationale 2027 Q&A| Instant
Download Pdf.
1. In a vapor-compression air-conditioning system, what is the primary
function of the compressor?
A. To reduce the temperature of liquid refrigerant entering the
evaporator
B. To absorb heat from the conditioned space
C. To raise the pressure and temperature of refrigerant vapor and move
it through the system
D. To remove moisture from the refrigerant
The compressor raises low-pressure refrigerant vapor to a higher
pressure and temperature while providing the force necessary to
circulate refrigerant through the system.
2. Which component of a typical refrigeration system is responsible
for rejecting heat from the refrigerant to the surrounding
environment?
,A. Evaporator
B. Condenser
C. Accumulator
D. Expansion valve
The condenser removes heat from the high-pressure refrigerant vapor,
causing it to condense into a high-pressure liquid.
3. What occurs when high-pressure liquid refrigerant passes through a
metering device such as a thermostatic expansion valve?
A. Its pressure increases while its temperature decreases
B. Its pressure decreases, causing part of the refrigerant to flash into
vapor
C. Its pressure and temperature both increase
D. It becomes superheated vapor without any pressure change
The metering device creates a pressure drop that reduces the
refrigerant's saturation temperature and causes a portion of the liquid
to flash into vapor.
4. What is the primary purpose of the evaporator in an air-
conditioning system?
A. To reject heat into outdoor air
B. To compress refrigerant vapor
C. To absorb heat from the conditioned space
D. To increase refrigerant pressure
,The evaporator absorbs heat from indoor air or another conditioned
medium as refrigerant evaporates at a low pressure and temperature.
5. A technician measures refrigerant entering the compressor as a
low-pressure vapor. What condition should normally exist at the
compressor inlet to protect the compressor from liquid damage?
A. Subcooled liquid
B. Saturated liquid
C. Superheated vapor
D. High-pressure liquid
Superheated vapor at the compressor inlet helps prevent liquid
refrigerant from entering the compressor, where liquid can cause
mechanical damage.
6. What is the principal purpose of superheat measurement in a
conventional direct-expansion evaporator?
A. To determine condenser subcooling
B. To evaluate evaporator refrigerant feeding and help prevent liquid
return to the compressor
C. To determine electrical resistance
D. To measure compressor oil pressure
Evaporator superheat provides information about how completely
refrigerant has boiled off and helps ensure that vapor rather than liquid
reaches the compressor.
, 7. What does subcooling describe in a refrigeration system?
A. Vapor temperature above its saturation temperature
B. Liquid temperature below its saturation temperature at a given
pressure
C. Refrigerant temperature above compressor discharge temperature
D. Air temperature below room temperature
Subcooling occurs when liquid refrigerant is cooled below its saturation
temperature at the corresponding pressure, providing a margin against
flashing before the metering device.
8. A normally operating air-cooled condenser becomes severely
blocked with dirt. What is the most likely immediate effect?
A. Condensing pressure decreases substantially
B. Condensing pressure increases because heat rejection is restricted
C. Evaporator pressure becomes atmospheric
D. Compressor amperage always decreases
Restricted condenser airflow reduces the system's ability to reject heat,
causing condensing temperature and pressure to rise.
9. What is the purpose of a liquid-line filter-drier?
A. To increase refrigerant pressure
B. To separate oil from refrigerant
C. To 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 air-conditioning system, what is the primary
function of the compressor?
A. To reduce the temperature of liquid refrigerant entering the
evaporator
B. To absorb heat from the conditioned space
C. To raise the pressure and temperature of refrigerant vapor and move
it through the system
D. To remove moisture from the refrigerant
The compressor raises low-pressure refrigerant vapor to a higher
pressure and temperature while providing the force necessary to
circulate refrigerant through the system.
2. Which component of a typical refrigeration system is responsible
for rejecting heat from the refrigerant to the surrounding
environment?
,A. Evaporator
B. Condenser
C. Accumulator
D. Expansion valve
The condenser removes heat from the high-pressure refrigerant vapor,
causing it to condense into a high-pressure liquid.
3. What occurs when high-pressure liquid refrigerant passes through a
metering device such as a thermostatic expansion valve?
A. Its pressure increases while its temperature decreases
B. Its pressure decreases, causing part of the refrigerant to flash into
vapor
C. Its pressure and temperature both increase
D. It becomes superheated vapor without any pressure change
The metering device creates a pressure drop that reduces the
refrigerant's saturation temperature and causes a portion of the liquid
to flash into vapor.
4. What is the primary purpose of the evaporator in an air-
conditioning system?
A. To reject heat into outdoor air
B. To compress refrigerant vapor
C. To absorb heat from the conditioned space
D. To increase refrigerant pressure
,The evaporator absorbs heat from indoor air or another conditioned
medium as refrigerant evaporates at a low pressure and temperature.
5. A technician measures refrigerant entering the compressor as a
low-pressure vapor. What condition should normally exist at the
compressor inlet to protect the compressor from liquid damage?
A. Subcooled liquid
B. Saturated liquid
C. Superheated vapor
D. High-pressure liquid
Superheated vapor at the compressor inlet helps prevent liquid
refrigerant from entering the compressor, where liquid can cause
mechanical damage.
6. What is the principal purpose of superheat measurement in a
conventional direct-expansion evaporator?
A. To determine condenser subcooling
B. To evaluate evaporator refrigerant feeding and help prevent liquid
return to the compressor
C. To determine electrical resistance
D. To measure compressor oil pressure
Evaporator superheat provides information about how completely
refrigerant has boiled off and helps ensure that vapor rather than liquid
reaches the compressor.
, 7. What does subcooling describe in a refrigeration system?
A. Vapor temperature above its saturation temperature
B. Liquid temperature below its saturation temperature at a given
pressure
C. Refrigerant temperature above compressor discharge temperature
D. Air temperature below room temperature
Subcooling occurs when liquid refrigerant is cooled below its saturation
temperature at the corresponding pressure, providing a margin against
flashing before the metering device.
8. A normally operating air-cooled condenser becomes severely
blocked with dirt. What is the most likely immediate effect?
A. Condensing pressure decreases substantially
B. Condensing pressure increases because heat rejection is restricted
C. Evaporator pressure becomes atmospheric
D. Compressor amperage always decreases
Restricted condenser airflow reduces the system's ability to reject heat,
causing condensing temperature and pressure to rise.
9. What is the purpose of a liquid-line filter-drier?
A. To increase refrigerant pressure
B. To separate oil from refrigerant
C. To remove moisture, acids, and particulate contaminants from the
