STAR HVAC Mastery Exam Questions
And Correct Answers (Verified Answers)
Plus Rationales 2026 Q&A | Instant
Download Pdf
1. Which refrigerant has zero ozone depletion potential and low
global warming potential?
A. R-22
B. R-410A
C. R-134a
D. R-12
R-410A is a hydrofluorocarbon (HFC) refrigerant with zero ozone
depletion potential and lower environmental impact compared to
older CFCs and HCFCs.
2. What is the primary purpose of a TXV (Thermostatic Expansion
Valve)?
A. To compress refrigerant
B. To filter air
C. To regulate refrigerant flow into the evaporator
D. To increase system pressure
The TXV meters refrigerant into the evaporator to maintain
optimal superheat and system efficiency.
3. What is the function of a condensate drain in an HVAC system?
A. To circulate refrigerant
, B. To supply air
C. To remove water produced by condensation
D. To regulate temperature
Condensate drains prevent water accumulation that can cause
damage or mold growth.
4. In HVAC, what does SEER stand for?
A. Standard Energy Efficiency Rating
B. Seasonal Energy Efficiency Ratio
C. System Efficiency Evaluation Ratio
D. Standard Evaporator Efficiency Ratio
SEER measures cooling efficiency of an air conditioner over a
typical cooling season.
5. Which component of an air conditioning system compresses
refrigerant gas?
A. Evaporator
B. Expansion valve
C. Compressor
D. Condenser
The compressor raises refrigerant pressure and temperature,
allowing it to release heat in the condenser.
6. What is the typical color code for R-410A service ports?
A. Red
B. Blue
C. Pink and blue
D. Green
R-410A uses pink for high side and blue for low side to differentiate
service connections.
, 7. Which type of HVAC system uses water or steam to distribute
heat?
A. Forced air
B. Hydronic
C. VRF
D. Geothermal
Hydronic systems circulate heated water or steam through pipes
to radiators or fan coils.
8. What is superheat in HVAC terms?
A. Temperature of refrigerant below boiling point
B. Temperature of refrigerant vapor above its saturation point
C. Pressure in the condenser
D. Ambient air temperature
Superheat ensures that refrigerant leaving the evaporator is fully
vaporized, preventing liquid from reaching the compressor.
9. What is the main purpose of an air filter in HVAC systems?
A. Heat the air
B. Remove dust and particulates
C. Regulate humidity
D. Increase air pressure
Filters protect equipment and improve indoor air quality by
trapping dust, pollen, and debris.
10. What device protects an HVAC compressor from
overcurrent?
A. Expansion valve
B. Thermostat
C. Compressor overload relay
And Correct Answers (Verified Answers)
Plus Rationales 2026 Q&A | Instant
Download Pdf
1. Which refrigerant has zero ozone depletion potential and low
global warming potential?
A. R-22
B. R-410A
C. R-134a
D. R-12
R-410A is a hydrofluorocarbon (HFC) refrigerant with zero ozone
depletion potential and lower environmental impact compared to
older CFCs and HCFCs.
2. What is the primary purpose of a TXV (Thermostatic Expansion
Valve)?
A. To compress refrigerant
B. To filter air
C. To regulate refrigerant flow into the evaporator
D. To increase system pressure
The TXV meters refrigerant into the evaporator to maintain
optimal superheat and system efficiency.
3. What is the function of a condensate drain in an HVAC system?
A. To circulate refrigerant
, B. To supply air
C. To remove water produced by condensation
D. To regulate temperature
Condensate drains prevent water accumulation that can cause
damage or mold growth.
4. In HVAC, what does SEER stand for?
A. Standard Energy Efficiency Rating
B. Seasonal Energy Efficiency Ratio
C. System Efficiency Evaluation Ratio
D. Standard Evaporator Efficiency Ratio
SEER measures cooling efficiency of an air conditioner over a
typical cooling season.
5. Which component of an air conditioning system compresses
refrigerant gas?
A. Evaporator
B. Expansion valve
C. Compressor
D. Condenser
The compressor raises refrigerant pressure and temperature,
allowing it to release heat in the condenser.
6. What is the typical color code for R-410A service ports?
A. Red
B. Blue
C. Pink and blue
D. Green
R-410A uses pink for high side and blue for low side to differentiate
service connections.
, 7. Which type of HVAC system uses water or steam to distribute
heat?
A. Forced air
B. Hydronic
C. VRF
D. Geothermal
Hydronic systems circulate heated water or steam through pipes
to radiators or fan coils.
8. What is superheat in HVAC terms?
A. Temperature of refrigerant below boiling point
B. Temperature of refrigerant vapor above its saturation point
C. Pressure in the condenser
D. Ambient air temperature
Superheat ensures that refrigerant leaving the evaporator is fully
vaporized, preventing liquid from reaching the compressor.
9. What is the main purpose of an air filter in HVAC systems?
A. Heat the air
B. Remove dust and particulates
C. Regulate humidity
D. Increase air pressure
Filters protect equipment and improve indoor air quality by
trapping dust, pollen, and debris.
10. What device protects an HVAC compressor from
overcurrent?
A. Expansion valve
B. Thermostat
C. Compressor overload relay
