Texas ACR Contractor Class A Exam Verified
Questions, Correct Answers, and Detailed
Explanations for Science Students||Already Graded
A+
1. What does Class A licensing allow a contractor to work on?
A. Systems up to 10 tons
B. Systems up to 25 tons
C. Residential systems only
D. Any size system
Class A contractors may install and service HVAC systems of unlimited
capacity.
2. Which refrigerant is classified as A1 (low toxicity, non-
flammable)?
A. R-290
B. R-32
C. R-410A
D. R-717
R-410A is an A1 refrigerant under ASHRAE safety classification.
3. Superheat is the temperature of vapor above:
A. Condensing temperature
B. Ambient temperature
C. Saturation temperature at evaporator pressure
D. Compressor discharge temperature
Superheat measures how much heat is added after refrigerant fully
vaporizes.
,4. Subcooling refers to:
A. Cooling vapor below saturation
B. Cooling liquid refrigerant below its saturation temperature
C. Lowering room temperature
D. Compressor cooling
Subcooling ensures only liquid enters the metering device.
5. The primary purpose of a TXV is to:
A. Control head pressure
B. Maintain proper evaporator superheat
C. Increase compressor speed
D. Store refrigerant
A TXV meters refrigerant based on evaporator load.
6. Which law relates pressure and temperature of a gas?
A. Ohm’s Law
B. Gay-Lussac’s Law
C. Newton’s Law
D. Faraday’s Law
Gas pressure changes proportionally with temperature at constant
volume.
7. Minimum clearance in front of electrical panels (NEC) is:
A. 12 inches
B. 24 inches
C. 36 inches
D. 48 inches
NEC requires 3 feet of working space.
, 8. Which device protects against compressor short cycling?
A. Contactor
B. Time delay relay
C. Transformer
D. Capacitor
Time delays prevent rapid starts that damage compressors.
9. What is the typical airflow per ton for comfort cooling?
A. 200 CFM
B. 300 CFM
C. 400 CFM
D. 600 CFM
Standard design value for residential cooling.
10. Which component removes moisture from refrigerant?
A. Accumulator
B. Filter-drier
C. Sight glass
D. Receiver
Filter-driers remove moisture and contaminants.
11. A system with low suction and low head pressure likely has:
A. Overcharge
B. Dirty condenser
C. Low refrigerant charge
D. Bad TXV
Undercharge reduces system pressures.
Questions, Correct Answers, and Detailed
Explanations for Science Students||Already Graded
A+
1. What does Class A licensing allow a contractor to work on?
A. Systems up to 10 tons
B. Systems up to 25 tons
C. Residential systems only
D. Any size system
Class A contractors may install and service HVAC systems of unlimited
capacity.
2. Which refrigerant is classified as A1 (low toxicity, non-
flammable)?
A. R-290
B. R-32
C. R-410A
D. R-717
R-410A is an A1 refrigerant under ASHRAE safety classification.
3. Superheat is the temperature of vapor above:
A. Condensing temperature
B. Ambient temperature
C. Saturation temperature at evaporator pressure
D. Compressor discharge temperature
Superheat measures how much heat is added after refrigerant fully
vaporizes.
,4. Subcooling refers to:
A. Cooling vapor below saturation
B. Cooling liquid refrigerant below its saturation temperature
C. Lowering room temperature
D. Compressor cooling
Subcooling ensures only liquid enters the metering device.
5. The primary purpose of a TXV is to:
A. Control head pressure
B. Maintain proper evaporator superheat
C. Increase compressor speed
D. Store refrigerant
A TXV meters refrigerant based on evaporator load.
6. Which law relates pressure and temperature of a gas?
A. Ohm’s Law
B. Gay-Lussac’s Law
C. Newton’s Law
D. Faraday’s Law
Gas pressure changes proportionally with temperature at constant
volume.
7. Minimum clearance in front of electrical panels (NEC) is:
A. 12 inches
B. 24 inches
C. 36 inches
D. 48 inches
NEC requires 3 feet of working space.
, 8. Which device protects against compressor short cycling?
A. Contactor
B. Time delay relay
C. Transformer
D. Capacitor
Time delays prevent rapid starts that damage compressors.
9. What is the typical airflow per ton for comfort cooling?
A. 200 CFM
B. 300 CFM
C. 400 CFM
D. 600 CFM
Standard design value for residential cooling.
10. Which component removes moisture from refrigerant?
A. Accumulator
B. Filter-drier
C. Sight glass
D. Receiver
Filter-driers remove moisture and contaminants.
11. A system with low suction and low head pressure likely has:
A. Overcharge
B. Dirty condenser
C. Low refrigerant charge
D. Bad TXV
Undercharge reduces system pressures.
