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Indiana HVAC Technician Qualification
Advanced Practice Exam 2026 | 100
Questions & Answers with Detailed
Rationales | Complete Exam Prep &
Study Guide
1. A single-phase condensing unit has a rated-load current of 18 A. The
manufacturer specifies a maximum overcurrent protective device of 30 A.
Which device is most appropriate when the calculated circuit ampacity is 24
A?
A. 20 A breaker
B. 25 A breaker
C. 30 A breaker
D. 40 A breaker
Answer: 30 A breaker
Rationale: The maximum overcurrent protective device specified by the
equipment manufacturer must be respected, while the circuit conductors must
have adequate ampacity. A 30 A device is appropriate when permitted by the
equipment listing and installation requirements.
, 2. A compressor operates with a suction pressure corresponding to 40°F
saturated evaporating temperature and a suction-line temperature of 52°F.
What is the approximate superheat?
A. 8°F
B. 10°F
C. 12°F
D. 16°F
Answer: 12°F
Rationale: Superheat is the actual suction-line temperature minus the saturated
suction temperature: 52°F − 40°F = 12°F.
3. What is the primary purpose of a liquid-line filter-drier in a refrigeration
system?
A. Increase compressor capacity
B. Remove moisture and contaminants
C. Raise condensing pressure
D. Reduce evaporator temperature
Answer: Remove moisture and contaminants
Rationale: Filter-driers remove moisture, acid, debris, and other contaminants
that can damage compressors, metering devices, and other refrigeration
components.
4. A TXV system has a high superheat, low suction pressure, and a normal-to-
low liquid-line temperature. Which condition should be investigated first?
A. Excessive refrigerant charge
B. Restricted refrigerant flow
C. Oversized condenser
D. Excessive evaporator airflow
Answer: Restricted refrigerant flow
,Rationale: A restricted filter-drier, liquid line, TXV inlet screen, or other
restriction can starve the evaporator, producing high superheat and low suction
pressure.
5. What is the most important reason for evacuating a refrigeration system to
a deep vacuum before charging?
A. To increase compressor oil pressure
B. To remove air and moisture
C. To raise discharge temperature
D. To increase refrigerant density
Answer: To remove air and moisture
Rationale: Air and moisture are noncondensables and contaminants. Moisture
can freeze at metering devices and react with refrigerant/oil to form acids.
6. A technician measures 500 microns after evacuation and isolates the
system. The vacuum rises rapidly to 2,000 microns and continues climbing.
What is the most likely concern?
A. Proper evacuation
B. Excessive refrigerant charge
C. Moisture or a system leak
D. Oversized evaporator
Answer: Moisture or a system leak
Rationale: A rapid vacuum rise indicates that the system may still contain
moisture or has a leak allowing atmospheric pressure into the evacuated circuit.
7. What is the primary function of a compressor crankcase heater?
A. Increase evaporator pressure
B. Prevent liquid refrigerant migration into the compressor oil
C. Increase condenser airflow
D. Reduce compressor amperage during operation
, Answer: Prevent liquid refrigerant migration into the compressor oil
Rationale: A crankcase heater keeps refrigerant from migrating and condensing
in the compressor crankcase during off cycles, reducing liquid dilution of the oil
and potential compressor damage.
8. A condenser fan motor runs continuously even when the compressor is off.
Which component should be investigated first on a system using a
pressure-controlled fan cycle?
A. Evaporator coil
B. Condenser fan control
C. TXV bulb
D. Crankcase heater
Answer: Condenser fan control
Rationale: A failed or improperly adjusted fan-cycle control can cause the
condenser fan to operate continuously or at inappropriate pressures.
9. Which condition most commonly causes abnormally high condensing
pressure?
A. Low outdoor temperature alone
B. Dirty condenser coil
C. Low indoor load
D. Low refrigerant charge
Answer: Dirty condenser coil
Rationale: A dirty condenser reduces heat rejection, causing condensing
temperature and pressure to rise.
10.A refrigeration system has low suction pressure, low head pressure, high
superheat, and low subcooling. What condition is most likely?
A. Overcharge
B. Undercharge
Indiana HVAC Technician Qualification
Advanced Practice Exam 2026 | 100
Questions & Answers with Detailed
Rationales | Complete Exam Prep &
Study Guide
1. A single-phase condensing unit has a rated-load current of 18 A. The
manufacturer specifies a maximum overcurrent protective device of 30 A.
Which device is most appropriate when the calculated circuit ampacity is 24
A?
A. 20 A breaker
B. 25 A breaker
C. 30 A breaker
D. 40 A breaker
Answer: 30 A breaker
Rationale: The maximum overcurrent protective device specified by the
equipment manufacturer must be respected, while the circuit conductors must
have adequate ampacity. A 30 A device is appropriate when permitted by the
equipment listing and installation requirements.
, 2. A compressor operates with a suction pressure corresponding to 40°F
saturated evaporating temperature and a suction-line temperature of 52°F.
What is the approximate superheat?
A. 8°F
B. 10°F
C. 12°F
D. 16°F
Answer: 12°F
Rationale: Superheat is the actual suction-line temperature minus the saturated
suction temperature: 52°F − 40°F = 12°F.
3. What is the primary purpose of a liquid-line filter-drier in a refrigeration
system?
A. Increase compressor capacity
B. Remove moisture and contaminants
C. Raise condensing pressure
D. Reduce evaporator temperature
Answer: Remove moisture and contaminants
Rationale: Filter-driers remove moisture, acid, debris, and other contaminants
that can damage compressors, metering devices, and other refrigeration
components.
4. A TXV system has a high superheat, low suction pressure, and a normal-to-
low liquid-line temperature. Which condition should be investigated first?
A. Excessive refrigerant charge
B. Restricted refrigerant flow
C. Oversized condenser
D. Excessive evaporator airflow
Answer: Restricted refrigerant flow
,Rationale: A restricted filter-drier, liquid line, TXV inlet screen, or other
restriction can starve the evaporator, producing high superheat and low suction
pressure.
5. What is the most important reason for evacuating a refrigeration system to
a deep vacuum before charging?
A. To increase compressor oil pressure
B. To remove air and moisture
C. To raise discharge temperature
D. To increase refrigerant density
Answer: To remove air and moisture
Rationale: Air and moisture are noncondensables and contaminants. Moisture
can freeze at metering devices and react with refrigerant/oil to form acids.
6. A technician measures 500 microns after evacuation and isolates the
system. The vacuum rises rapidly to 2,000 microns and continues climbing.
What is the most likely concern?
A. Proper evacuation
B. Excessive refrigerant charge
C. Moisture or a system leak
D. Oversized evaporator
Answer: Moisture or a system leak
Rationale: A rapid vacuum rise indicates that the system may still contain
moisture or has a leak allowing atmospheric pressure into the evacuated circuit.
7. What is the primary function of a compressor crankcase heater?
A. Increase evaporator pressure
B. Prevent liquid refrigerant migration into the compressor oil
C. Increase condenser airflow
D. Reduce compressor amperage during operation
, Answer: Prevent liquid refrigerant migration into the compressor oil
Rationale: A crankcase heater keeps refrigerant from migrating and condensing
in the compressor crankcase during off cycles, reducing liquid dilution of the oil
and potential compressor damage.
8. A condenser fan motor runs continuously even when the compressor is off.
Which component should be investigated first on a system using a
pressure-controlled fan cycle?
A. Evaporator coil
B. Condenser fan control
C. TXV bulb
D. Crankcase heater
Answer: Condenser fan control
Rationale: A failed or improperly adjusted fan-cycle control can cause the
condenser fan to operate continuously or at inappropriate pressures.
9. Which condition most commonly causes abnormally high condensing
pressure?
A. Low outdoor temperature alone
B. Dirty condenser coil
C. Low indoor load
D. Low refrigerant charge
Answer: Dirty condenser coil
Rationale: A dirty condenser reduces heat rejection, causing condensing
temperature and pressure to rise.
10.A refrigeration system has low suction pressure, low head pressure, high
superheat, and low subcooling. What condition is most likely?
A. Overcharge
B. Undercharge
