HVAC CONTRACTOR PRACTICE EXAM Question
And Correct Answers (Verified Answers) Plus
Rationales 2026 Q&A |Instant Download Pdf
1.
Which refrigerant is used as a replacement for R-22 in many retrofit applications?
A. R-717
B. R-744
C. R-410A
D. R-123
Rationale: R-410A is the most common non-ozone-depleting replacement for R-
22 in residential and light commercial systems.
2.
What is the primary purpose of a TXV?
A. Add heat to the evaporator
B. Remove moisture from refrigerant
C. Maintain superheat at the evaporator outlet
D. Reduce discharge pressure
Rationale: A TXV meters refrigerant to maintain proper superheat and protect
the compressor.
3.
Which component compresses low-pressure vapor to high-pressure vapor?
A. Condenser
B. Compressor
C. Metering device
D. Evaporator
,Rationale: The compressor raises vapor pressure and circulates refrigerant
through the system.
4.
What does subcooling indicate?
A. Temperature above condensing temperature
B. Temperature below condensing temperature
C. Compressor discharge temperature
D. Evaporator saturation rate
Rationale: Subcooling measures how far the liquid refrigerant temperature is
below saturation in the condenser.
5.
Which refrigerant classification indicates low toxicity and low flammability?
A. B1
B. A1
C. A3
D. B3
Rationale: ASHRAE A1 refrigerants have low toxicity and low flammability.
6.
The minimum required evacuation level for an HCFC system containing less than
200 lbs of refrigerant is:
A. 500 microns
B. 2000 microns
C. 500 microns or lower
D. 50 microns
Rationale: EPA Section 608 requires evacuation to 500 microns for small HCFC
systems.
7.
Which device removes latent heat from the air?
A. Compressor
, B. Evaporator coil
C. Metering device
D. Condenser coil
Rationale: Moisture removal (latent heat) occurs at the evaporator coil during
dehumidification.
8.
What electrical meter setting is used to measure motor winding resistance?
A. AC volts
B. Ohms
C. Amps
D. Hertz
Rationale: Ohm measurement checks continuity and resistance in windings.
9.
Which tool is used to measure airflow through a duct?
A. Clamp meter
B. Micron gauge
C. Infrared thermometer
D. Anemometer
Rationale: Anemometers measure air velocity to calculate airflow.
10.
What happens when a blower motor capacitor fails?
A. The refrigerant overheats
B. The motor may not start or will run inefficiently
C. The compressor floods
D. The TXV closes fully
Rationale: Capacitors provide phase shift and torque; failure leads to weak or no
motor start.
11.
And Correct Answers (Verified Answers) Plus
Rationales 2026 Q&A |Instant Download Pdf
1.
Which refrigerant is used as a replacement for R-22 in many retrofit applications?
A. R-717
B. R-744
C. R-410A
D. R-123
Rationale: R-410A is the most common non-ozone-depleting replacement for R-
22 in residential and light commercial systems.
2.
What is the primary purpose of a TXV?
A. Add heat to the evaporator
B. Remove moisture from refrigerant
C. Maintain superheat at the evaporator outlet
D. Reduce discharge pressure
Rationale: A TXV meters refrigerant to maintain proper superheat and protect
the compressor.
3.
Which component compresses low-pressure vapor to high-pressure vapor?
A. Condenser
B. Compressor
C. Metering device
D. Evaporator
,Rationale: The compressor raises vapor pressure and circulates refrigerant
through the system.
4.
What does subcooling indicate?
A. Temperature above condensing temperature
B. Temperature below condensing temperature
C. Compressor discharge temperature
D. Evaporator saturation rate
Rationale: Subcooling measures how far the liquid refrigerant temperature is
below saturation in the condenser.
5.
Which refrigerant classification indicates low toxicity and low flammability?
A. B1
B. A1
C. A3
D. B3
Rationale: ASHRAE A1 refrigerants have low toxicity and low flammability.
6.
The minimum required evacuation level for an HCFC system containing less than
200 lbs of refrigerant is:
A. 500 microns
B. 2000 microns
C. 500 microns or lower
D. 50 microns
Rationale: EPA Section 608 requires evacuation to 500 microns for small HCFC
systems.
7.
Which device removes latent heat from the air?
A. Compressor
, B. Evaporator coil
C. Metering device
D. Condenser coil
Rationale: Moisture removal (latent heat) occurs at the evaporator coil during
dehumidification.
8.
What electrical meter setting is used to measure motor winding resistance?
A. AC volts
B. Ohms
C. Amps
D. Hertz
Rationale: Ohm measurement checks continuity and resistance in windings.
9.
Which tool is used to measure airflow through a duct?
A. Clamp meter
B. Micron gauge
C. Infrared thermometer
D. Anemometer
Rationale: Anemometers measure air velocity to calculate airflow.
10.
What happens when a blower motor capacitor fails?
A. The refrigerant overheats
B. The motor may not start or will run inefficiently
C. The compressor floods
D. The TXV closes fully
Rationale: Capacitors provide phase shift and torque; failure leads to weak or no
motor start.
11.
