Wisconsin Refrigeration Systems
Contractor Exam Practice Questions
And Correct Answers (Verified
Answers) Plus Rationale 2027 Q&A|
Instant Download Pdf.
1. In a commercial refrigeration system, what is the primary function
of the compressor?
A. Remove moisture from the refrigerant
B. Lower the refrigerant pressure before the evaporator
C. Raise the pressure and temperature of refrigerant vapor so it can
reject heat in the condenser
D. Meter liquid refrigerant into the condenser
The compressor takes low-pressure refrigerant vapor from the
evaporator and compresses it into a high-pressure, higher-temperature
vapor suitable for heat rejection in the condenser.
2. Which component is primarily responsible for removing heat from
the refrigerated space?
A. Condenser
B. Compressor
C. Receiver
D. Evaporator
,The evaporator absorbs heat from the refrigerated space as refrigerant
evaporates at a low pressure and temperature.
3. What is the primary purpose of a thermostatic expansion valve
(TXV)?
A. Increase compressor discharge pressure
B. Meter refrigerant into the evaporator while controlling superheat
C. Remove noncondensable gases
D. Store excess liquid refrigerant
A TXV regulates refrigerant flow into the evaporator and responds to
evaporator outlet conditions to maintain an appropriate superheat.
4. Refrigerant superheat is best described as:
A. The temperature of saturated liquid above its boiling point
B. The difference between condensing and evaporating pressure
C. The temperature of vapor above its saturation temperature at a given
pressure
D. The difference between compressor discharge and suction
temperatures
Superheat is the amount by which a vapor's actual temperature exceeds
its saturation temperature at the measured pressure.
5. What is subcooling?
A. Cooling vapor below its evaporating temperature
B. Cooling liquid refrigerant below its saturation temperature at the
measured pressure
,C. Cooling the compressor below room temperature
D. Reducing suction pressure below atmospheric pressure
Subcooling indicates that liquid refrigerant has been cooled below its
saturation temperature, helping ensure solid liquid reaches the
metering device.
6. Excessively high evaporator superheat may indicate:
A. An overfed evaporator
B. Excessive liquid returning to the compressor
C. Insufficient refrigerant flow through the evaporator
D. Excessive condenser flooding
High superheat commonly indicates that the evaporator is being starved
because insufficient refrigerant is entering or because heat transfer or
system conditions are abnormal.
7. What condition is most likely to result from excessive liquid
refrigerant returning to a reciprocating compressor?
A. Condenser starvation
B. Liquid slugging and compressor damage
C. Reduced receiver capacity only
D. Increased evaporator superheat
Compressors are designed to compress vapor, not liquid. Liquid entering
the cylinders can cause mechanical damage, commonly called slugging.
8. What is the primary function of a liquid receiver in a refrigeration
system?
, A. Separate oil from discharge vapor
B. Increase compressor capacity
C. Store liquid refrigerant during varying operating conditions
D. Remove heat from the compressor motor
A receiver provides a controlled storage location for liquid refrigerant
and helps accommodate changing system charge requirements.
9. A filter-drier installed in a liquid line primarily removes:
A. Oil and refrigerant vapor
B. Moisture, acids, and particulate contaminants
C. Heat and pressure
D. Nitrogen and oxygen from the compressor
The filter-drier protects refrigeration components by capturing
contaminants and chemically or physically removing moisture and other
harmful substances.
10. Why is moisture particularly dangerous in a refrigeration
system?
A. It always increases refrigerant capacity
B. It prevents all refrigerant evaporation
C. It can cause corrosion, acid formation, ice formation, and metering-
device problems
D. It permanently increases condenser airflow
Moisture can react with refrigerant and oil to form corrosive compounds
and can freeze at restrictive points, interfering with refrigerant flow.
Contractor Exam Practice Questions
And Correct Answers (Verified
Answers) Plus Rationale 2027 Q&A|
Instant Download Pdf.
1. In a commercial refrigeration system, what is the primary function
of the compressor?
A. Remove moisture from the refrigerant
B. Lower the refrigerant pressure before the evaporator
C. Raise the pressure and temperature of refrigerant vapor so it can
reject heat in the condenser
D. Meter liquid refrigerant into the condenser
The compressor takes low-pressure refrigerant vapor from the
evaporator and compresses it into a high-pressure, higher-temperature
vapor suitable for heat rejection in the condenser.
2. Which component is primarily responsible for removing heat from
the refrigerated space?
A. Condenser
B. Compressor
C. Receiver
D. Evaporator
,The evaporator absorbs heat from the refrigerated space as refrigerant
evaporates at a low pressure and temperature.
3. What is the primary purpose of a thermostatic expansion valve
(TXV)?
A. Increase compressor discharge pressure
B. Meter refrigerant into the evaporator while controlling superheat
C. Remove noncondensable gases
D. Store excess liquid refrigerant
A TXV regulates refrigerant flow into the evaporator and responds to
evaporator outlet conditions to maintain an appropriate superheat.
4. Refrigerant superheat is best described as:
A. The temperature of saturated liquid above its boiling point
B. The difference between condensing and evaporating pressure
C. The temperature of vapor above its saturation temperature at a given
pressure
D. The difference between compressor discharge and suction
temperatures
Superheat is the amount by which a vapor's actual temperature exceeds
its saturation temperature at the measured pressure.
5. What is subcooling?
A. Cooling vapor below its evaporating temperature
B. Cooling liquid refrigerant below its saturation temperature at the
measured pressure
,C. Cooling the compressor below room temperature
D. Reducing suction pressure below atmospheric pressure
Subcooling indicates that liquid refrigerant has been cooled below its
saturation temperature, helping ensure solid liquid reaches the
metering device.
6. Excessively high evaporator superheat may indicate:
A. An overfed evaporator
B. Excessive liquid returning to the compressor
C. Insufficient refrigerant flow through the evaporator
D. Excessive condenser flooding
High superheat commonly indicates that the evaporator is being starved
because insufficient refrigerant is entering or because heat transfer or
system conditions are abnormal.
7. What condition is most likely to result from excessive liquid
refrigerant returning to a reciprocating compressor?
A. Condenser starvation
B. Liquid slugging and compressor damage
C. Reduced receiver capacity only
D. Increased evaporator superheat
Compressors are designed to compress vapor, not liquid. Liquid entering
the cylinders can cause mechanical damage, commonly called slugging.
8. What is the primary function of a liquid receiver in a refrigeration
system?
, A. Separate oil from discharge vapor
B. Increase compressor capacity
C. Store liquid refrigerant during varying operating conditions
D. Remove heat from the compressor motor
A receiver provides a controlled storage location for liquid refrigerant
and helps accommodate changing system charge requirements.
9. A filter-drier installed in a liquid line primarily removes:
A. Oil and refrigerant vapor
B. Moisture, acids, and particulate contaminants
C. Heat and pressure
D. Nitrogen and oxygen from the compressor
The filter-drier protects refrigeration components by capturing
contaminants and chemically or physically removing moisture and other
harmful substances.
10. Why is moisture particularly dangerous in a refrigeration
system?
A. It always increases refrigerant capacity
B. It prevents all refrigerant evaporation
C. It can cause corrosion, acid formation, ice formation, and metering-
device problems
D. It permanently increases condenser airflow
Moisture can react with refrigerant and oil to form corrosive compounds
and can freeze at restrictive points, interfering with refrigerant flow.
