HVAC Excellence Professional Technician
Newest Updated 150 Questions And
Correct Answers From Actual Past
Papers Exams (Graded A+) Plus
Rationales 2025|2026 Q&A | Instant
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1. What is the primary purpose of a refrigeration system compressor?
A. To remove moisture from refrigerant
B. To increase refrigerant pressure and move refrigerant through the system
C. To reduce refrigerant temperature before expansion
D. To measure refrigerant superheat
Answer: B. To increase refrigerant pressure and move refrigerant through the
system
The compressor raises the pressure and temperature of the refrigerant vapor and
circulates refrigerant through the refrigeration cycle.
2. In a properly operating refrigeration system, where does the refrigerant
absorb heat?
A. Condenser
B. Compressor
C. Evaporator
D. Receiver
Answer: C. Evaporator
,The evaporator absorbs heat from the conditioned space as the refrigerant
changes from a low-pressure liquid/vapor mixture into vapor.
3. What instrument is used to measure refrigerant pressure?
A. Thermometer
B. Manifold gauge set
C. Hygrometer
D. Ammeter
Answer: B. Manifold gauge set
HVAC technicians use manifold gauges to measure low-side and high-side
refrigerant pressures during diagnosis and charging.
4. What is superheat?
A. The temperature of liquid refrigerant above saturation temperature
B. The temperature of vapor refrigerant above its saturation temperature
C. The pressure difference across a compressor
D. The temperature difference between supply and return air
Answer: B. The temperature of vapor refrigerant above its saturation
temperature
Superheat confirms that refrigerant leaving the evaporator is vapor and helps
prevent liquid refrigerant from entering the compressor.
5. What component removes heat from refrigerant vapor?
A. Evaporator
B. Expansion valve
C. Condenser
D. Accumulator
Answer: C. Condenser
The condenser rejects heat from the refrigerant and changes high-pressure vapor
into high-pressure liquid.
, 6. What type of refrigerant metering device responds to evaporator load
changes?
A. Fixed orifice
B. Capillary tube
C. Thermostatic expansion valve
D. Receiver
Answer: C. Thermostatic expansion valve
The thermostatic expansion valve adjusts refrigerant flow based on evaporator
outlet superheat.
7. What does HVAC stand for?
A. Heating Ventilation and Air Conditioning
B. Heat Valve Air Control
C. High Voltage Air Circuit
D. Heating Vapor Adjustment Control
Answer: A. Heating Ventilation and Air Conditioning
HVAC systems provide heating, ventilation, and air conditioning for comfort and
indoor air quality.
8. A dirty air filter will most commonly cause:
A. Increased airflow
B. Reduced airflow
C. Increased refrigerant charge
D. Higher voltage supply
Answer: B. Reduced airflow
A restricted filter reduces air movement across the evaporator, which can cause
poor cooling performance and coil freezing.
9. What is the purpose of a blower motor in an air conditioning system?
, A. Compress refrigerant
B. Move air across the evaporator and into the conditioned space
C. Control refrigerant pressure
D. Remove oil from refrigerant
Answer: B. Move air across the evaporator and into the conditioned space
The blower circulates conditioned air through the duct system.
10.Which refrigerant property is important for identifying refrigerant leaks?
A. Color
B. Odor
C. Pressure relationship with temperature
D. Electrical resistance
Answer: C. Pressure relationship with temperature
Technicians use pressure-temperature charts to determine refrigerant conditions
and diagnose system problems.
11.What is the purpose of a contactor in an HVAC electrical system?
A. Reduce refrigerant pressure
B. Switch high-voltage power to components
C. Measure airflow
D. Remove humidity
Answer: B. Switch high-voltage power to components
The contactor uses a low-voltage control signal to energize high-voltage
components such as compressors and condenser fans.
12.What device protects a compressor from excessive electrical current?
A. Thermostat
B. Fuse or circuit breaker
C. Filter drier
D. Expansion valve
Newest Updated 150 Questions And
Correct Answers From Actual Past
Papers Exams (Graded A+) Plus
Rationales 2025|2026 Q&A | Instant
Download Pdf
1. What is the primary purpose of a refrigeration system compressor?
A. To remove moisture from refrigerant
B. To increase refrigerant pressure and move refrigerant through the system
C. To reduce refrigerant temperature before expansion
D. To measure refrigerant superheat
Answer: B. To increase refrigerant pressure and move refrigerant through the
system
The compressor raises the pressure and temperature of the refrigerant vapor and
circulates refrigerant through the refrigeration cycle.
2. In a properly operating refrigeration system, where does the refrigerant
absorb heat?
A. Condenser
B. Compressor
C. Evaporator
D. Receiver
Answer: C. Evaporator
,The evaporator absorbs heat from the conditioned space as the refrigerant
changes from a low-pressure liquid/vapor mixture into vapor.
3. What instrument is used to measure refrigerant pressure?
A. Thermometer
B. Manifold gauge set
C. Hygrometer
D. Ammeter
Answer: B. Manifold gauge set
HVAC technicians use manifold gauges to measure low-side and high-side
refrigerant pressures during diagnosis and charging.
4. What is superheat?
A. The temperature of liquid refrigerant above saturation temperature
B. The temperature of vapor refrigerant above its saturation temperature
C. The pressure difference across a compressor
D. The temperature difference between supply and return air
Answer: B. The temperature of vapor refrigerant above its saturation
temperature
Superheat confirms that refrigerant leaving the evaporator is vapor and helps
prevent liquid refrigerant from entering the compressor.
5. What component removes heat from refrigerant vapor?
A. Evaporator
B. Expansion valve
C. Condenser
D. Accumulator
Answer: C. Condenser
The condenser rejects heat from the refrigerant and changes high-pressure vapor
into high-pressure liquid.
, 6. What type of refrigerant metering device responds to evaporator load
changes?
A. Fixed orifice
B. Capillary tube
C. Thermostatic expansion valve
D. Receiver
Answer: C. Thermostatic expansion valve
The thermostatic expansion valve adjusts refrigerant flow based on evaporator
outlet superheat.
7. What does HVAC stand for?
A. Heating Ventilation and Air Conditioning
B. Heat Valve Air Control
C. High Voltage Air Circuit
D. Heating Vapor Adjustment Control
Answer: A. Heating Ventilation and Air Conditioning
HVAC systems provide heating, ventilation, and air conditioning for comfort and
indoor air quality.
8. A dirty air filter will most commonly cause:
A. Increased airflow
B. Reduced airflow
C. Increased refrigerant charge
D. Higher voltage supply
Answer: B. Reduced airflow
A restricted filter reduces air movement across the evaporator, which can cause
poor cooling performance and coil freezing.
9. What is the purpose of a blower motor in an air conditioning system?
, A. Compress refrigerant
B. Move air across the evaporator and into the conditioned space
C. Control refrigerant pressure
D. Remove oil from refrigerant
Answer: B. Move air across the evaporator and into the conditioned space
The blower circulates conditioned air through the duct system.
10.Which refrigerant property is important for identifying refrigerant leaks?
A. Color
B. Odor
C. Pressure relationship with temperature
D. Electrical resistance
Answer: C. Pressure relationship with temperature
Technicians use pressure-temperature charts to determine refrigerant conditions
and diagnose system problems.
11.What is the purpose of a contactor in an HVAC electrical system?
A. Reduce refrigerant pressure
B. Switch high-voltage power to components
C. Measure airflow
D. Remove humidity
Answer: B. Switch high-voltage power to components
The contactor uses a low-voltage control signal to energize high-voltage
components such as compressors and condenser fans.
12.What device protects a compressor from excessive electrical current?
A. Thermostat
B. Fuse or circuit breaker
C. Filter drier
D. Expansion valve
