Master Refrigeration Technician Exam
Practice Questions And Correct Answers
(Verified Answers) Plus Rationale 2026
Q&A| Instant Download Pdf
1.A refrigeration system is operating with a low suction pressure, high
superheat, and a normal-to-low condenser pressure. Which condition is
most likely causing this operating pattern?
A. Overcharged refrigerant system
B. Restricted metering device or insufficient refrigerant feed
C. Dirty condenser coil causing poor heat rejection
D. Excessive airflow across the evaporator
Answer: B. Restricted metering device or insufficient refrigerant feed
A restricted metering device prevents adequate refrigerant from entering
the evaporator, causing low suction pressure and high superheat because
the evaporator becomes starved of refrigerant.
2. In a vapor-compression refrigeration system, the primary purpose of
the compressor is to:
A. Convert high-pressure liquid refrigerant into low-pressure vapor
B. Remove heat from the conditioned space
C. Increase refrigerant pressure and temperature by compressing vapor
D. Control refrigerant flow into the evaporator
,Answer: C. Increase refrigerant pressure and temperature by compressing
vapor
The compressor raises the pressure and temperature of refrigerant vapor
so it can release heat in the condenser and continue the refrigeration cycle.
3. A refrigeration technician measures high discharge pressure, high
condensing temperature, and normal suction pressure. Which
problem should be suspected first?
A. Dirty condenser or inadequate condenser airflow
B. Low refrigerant charge
C. Failed evaporator fan motor
D. Restricted suction line
Answer: A. Dirty condenser or inadequate condenser airflow
Poor condenser heat rejection causes refrigerant pressure and temperature
to rise because heat cannot effectively leave the system.
4. The main function of a thermostatic expansion valve (TXV) in a
refrigeration system is to:
A. Maintain proper evaporator superheat by controlling refrigerant flow
B. Increase compressor discharge pressure
C. Remove oil from the refrigerant circuit
D. Prevent condenser flooding
Answer: A. Maintain proper evaporator superheat by controlling
refrigerant flow
A TXV adjusts refrigerant flow into the evaporator to maintain a desired
superheat level and optimize evaporator performance.
5. What instrument is primarily used to measure refrigerant pressure
during service procedures?
,A. Megohmmeter
B. Manifold gauge set
C. Clamp ammeter
D. Micrometer
Answer: B. Manifold gauge set
A manifold gauge set allows technicians to measure suction and discharge
pressures and assist with system diagnosis and charging.
6. Excessive refrigerant charge in a refrigeration system typically causes:
A. Low head pressure and low subcooling
B. High head pressure and excessive subcooling
C. Low suction pressure and high superheat
D. Reduced compressor oil level only
Answer: B. High head pressure and excessive subcooling
An overcharged system contains excess liquid refrigerant in the condenser,
increasing condensing pressure and subcooling.
7. The process of removing moisture and non-condensable gases from a
refrigeration system before charging is called:
A. Recovery
B. Evacuation
C. Condensation
D. Compression
Answer: B. Evacuation
Evacuation removes air and moisture from the refrigeration circuit using a
vacuum pump before refrigerant is introduced.
8. A micron gauge is used by refrigeration technicians to:
, A. Measure refrigerant temperature
B. Measure vacuum depth during evacuation
C. Determine compressor horsepower
D. Measure electrical resistance
Answer: B. Measure vacuum depth during evacuation
A micron gauge provides an accurate measurement of system vacuum
levels, confirming proper dehydration before charging.
9. Refrigerant subcooling is the process of:
A. Heating vapor above saturation temperature
B. Cooling liquid refrigerant below its condensing temperature
C. Increasing compressor suction pressure
D. Reducing evaporator airflow
Answer: B. Cooling liquid refrigerant below its condensing temperature
Subcooling ensures that refrigerant entering the expansion device is fully
liquid and improves system efficiency.
10. Refrigerant superheat refers to:
A. The temperature of liquid refrigerant above saturation temperature
B. The pressure difference between suction and discharge
C. The temperature of vapor refrigerant above its saturation point
D. The temperature difference across the condenser only
Answer: C. The temperature of vapor refrigerant above its saturation point
Superheat measures how much vapor temperature exceeds the
refrigerant’s boiling temperature and helps prevent liquid refrigerant from
entering the compressor.
11. A compressor experiencing repeated overheating may be
damaged by:
Practice Questions And Correct Answers
(Verified Answers) Plus Rationale 2026
Q&A| Instant Download Pdf
1.A refrigeration system is operating with a low suction pressure, high
superheat, and a normal-to-low condenser pressure. Which condition is
most likely causing this operating pattern?
A. Overcharged refrigerant system
B. Restricted metering device or insufficient refrigerant feed
C. Dirty condenser coil causing poor heat rejection
D. Excessive airflow across the evaporator
Answer: B. Restricted metering device or insufficient refrigerant feed
A restricted metering device prevents adequate refrigerant from entering
the evaporator, causing low suction pressure and high superheat because
the evaporator becomes starved of refrigerant.
2. In a vapor-compression refrigeration system, the primary purpose of
the compressor is to:
A. Convert high-pressure liquid refrigerant into low-pressure vapor
B. Remove heat from the conditioned space
C. Increase refrigerant pressure and temperature by compressing vapor
D. Control refrigerant flow into the evaporator
,Answer: C. Increase refrigerant pressure and temperature by compressing
vapor
The compressor raises the pressure and temperature of refrigerant vapor
so it can release heat in the condenser and continue the refrigeration cycle.
3. A refrigeration technician measures high discharge pressure, high
condensing temperature, and normal suction pressure. Which
problem should be suspected first?
A. Dirty condenser or inadequate condenser airflow
B. Low refrigerant charge
C. Failed evaporator fan motor
D. Restricted suction line
Answer: A. Dirty condenser or inadequate condenser airflow
Poor condenser heat rejection causes refrigerant pressure and temperature
to rise because heat cannot effectively leave the system.
4. The main function of a thermostatic expansion valve (TXV) in a
refrigeration system is to:
A. Maintain proper evaporator superheat by controlling refrigerant flow
B. Increase compressor discharge pressure
C. Remove oil from the refrigerant circuit
D. Prevent condenser flooding
Answer: A. Maintain proper evaporator superheat by controlling
refrigerant flow
A TXV adjusts refrigerant flow into the evaporator to maintain a desired
superheat level and optimize evaporator performance.
5. What instrument is primarily used to measure refrigerant pressure
during service procedures?
,A. Megohmmeter
B. Manifold gauge set
C. Clamp ammeter
D. Micrometer
Answer: B. Manifold gauge set
A manifold gauge set allows technicians to measure suction and discharge
pressures and assist with system diagnosis and charging.
6. Excessive refrigerant charge in a refrigeration system typically causes:
A. Low head pressure and low subcooling
B. High head pressure and excessive subcooling
C. Low suction pressure and high superheat
D. Reduced compressor oil level only
Answer: B. High head pressure and excessive subcooling
An overcharged system contains excess liquid refrigerant in the condenser,
increasing condensing pressure and subcooling.
7. The process of removing moisture and non-condensable gases from a
refrigeration system before charging is called:
A. Recovery
B. Evacuation
C. Condensation
D. Compression
Answer: B. Evacuation
Evacuation removes air and moisture from the refrigeration circuit using a
vacuum pump before refrigerant is introduced.
8. A micron gauge is used by refrigeration technicians to:
, A. Measure refrigerant temperature
B. Measure vacuum depth during evacuation
C. Determine compressor horsepower
D. Measure electrical resistance
Answer: B. Measure vacuum depth during evacuation
A micron gauge provides an accurate measurement of system vacuum
levels, confirming proper dehydration before charging.
9. Refrigerant subcooling is the process of:
A. Heating vapor above saturation temperature
B. Cooling liquid refrigerant below its condensing temperature
C. Increasing compressor suction pressure
D. Reducing evaporator airflow
Answer: B. Cooling liquid refrigerant below its condensing temperature
Subcooling ensures that refrigerant entering the expansion device is fully
liquid and improves system efficiency.
10. Refrigerant superheat refers to:
A. The temperature of liquid refrigerant above saturation temperature
B. The pressure difference between suction and discharge
C. The temperature of vapor refrigerant above its saturation point
D. The temperature difference across the condenser only
Answer: C. The temperature of vapor refrigerant above its saturation point
Superheat measures how much vapor temperature exceeds the
refrigerant’s boiling temperature and helps prevent liquid refrigerant from
entering the compressor.
11. A compressor experiencing repeated overheating may be
damaged by:
