UA STAR HVACR Mastery Certification
Exam Practice Questions And Correct
Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant
Download Pdf
1. What does the superheat value indicate in a refrigeration system?
A. The subcooling level
B. The amount of heat added to refrigerant after evaporation
C. The condenser saturation temperature
D. The compressor discharge temperature
Superheat ensures refrigerant vapor leaving the evaporator is fully
vapor to protect the compressor.
2. What is the primary function of a thermostatic expansion valve (TXV)?
A. Maintain constant discharge pressure
B. Regulate refrigerant flow into the evaporator
, C. Increase compressor efficiency
D. Reduce condenser pressure
TXVs meter refrigerant based on load to maintain proper superheat.
3. Which refrigerant has the lowest ozone depletion potential (ODP)?
A. R-22
B. R-123
C. R-410A
D. R-12
R-410A has zero ODP unlike R-22 and older CFCs/HCFCs.
4. What is the standard voltage for most residential split-system
condensers in the U.S.?
A. 120V single-phase
B. 240V single-phase
C. 480V three-phase
D. 208V single-phase
Residential outdoor units typically use 240V for compressor and fan
motor.
5. Which tool is used to remove non-condensables in a sealed
refrigeration system?
A. Recovery machine
B. Vacuum pump
C. Both A and B
D. Manifold gauge set only
, Recovery removes refrigerant; vacuum pump removes moisture &
air.
6. What does a high subcooling reading usually indicate?
A. Low refrigerant charge
B. Overcharge or restricted metering device
C. Low condenser efficiency
D. Evaporator floodback
Liquid backs up in condenser when overcharged or restricted.
7. What component separates liquid from vapor to protect a
compressor?
A. TXV
B. Suction accumulator
C. Receiver
D. Liquid line filter
Accumulators prevent liquid slugging into compressor.
8. Which meter tests microfarads on a capacitor?
A. Clamp meter
B. Megohmmeter
C. Multimeter with capacitance function
D. Psychrometer
Capacitance mode measures microfarad values.
9. In a three-phase motor, what causes reverse rotation?
A. Low voltage
Exam Practice Questions And Correct
Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant
Download Pdf
1. What does the superheat value indicate in a refrigeration system?
A. The subcooling level
B. The amount of heat added to refrigerant after evaporation
C. The condenser saturation temperature
D. The compressor discharge temperature
Superheat ensures refrigerant vapor leaving the evaporator is fully
vapor to protect the compressor.
2. What is the primary function of a thermostatic expansion valve (TXV)?
A. Maintain constant discharge pressure
B. Regulate refrigerant flow into the evaporator
, C. Increase compressor efficiency
D. Reduce condenser pressure
TXVs meter refrigerant based on load to maintain proper superheat.
3. Which refrigerant has the lowest ozone depletion potential (ODP)?
A. R-22
B. R-123
C. R-410A
D. R-12
R-410A has zero ODP unlike R-22 and older CFCs/HCFCs.
4. What is the standard voltage for most residential split-system
condensers in the U.S.?
A. 120V single-phase
B. 240V single-phase
C. 480V three-phase
D. 208V single-phase
Residential outdoor units typically use 240V for compressor and fan
motor.
5. Which tool is used to remove non-condensables in a sealed
refrigeration system?
A. Recovery machine
B. Vacuum pump
C. Both A and B
D. Manifold gauge set only
, Recovery removes refrigerant; vacuum pump removes moisture &
air.
6. What does a high subcooling reading usually indicate?
A. Low refrigerant charge
B. Overcharge or restricted metering device
C. Low condenser efficiency
D. Evaporator floodback
Liquid backs up in condenser when overcharged or restricted.
7. What component separates liquid from vapor to protect a
compressor?
A. TXV
B. Suction accumulator
C. Receiver
D. Liquid line filter
Accumulators prevent liquid slugging into compressor.
8. Which meter tests microfarads on a capacitor?
A. Clamp meter
B. Megohmmeter
C. Multimeter with capacitance function
D. Psychrometer
Capacitance mode measures microfarad values.
9. In a three-phase motor, what causes reverse rotation?
A. Low voltage
