AZ L-74 HVAC CONTRACTOR EXAM
Questions And Correct Answers
(Verified Answers) Plus Rationale2026
Q&A| Instant Download Pdf
1. What is the primary purpose of an expansion valve in a refrigeration
cycle?
A. Increase refrigerant pressure
B. Reduce refrigerant pressure and control flow
C. Compress refrigerant vapor
D. Superheat the refrigerant
Rationale: The expansion valve meters refrigerant into the evaporator and
drops its pressure for proper cooling.
2. Which type of refrigerant is commonly classified as an HFC?
A. R-22
B. R-410A
C. R-12
D. R-717
Rationale: R-410A is a hydrofluorocarbon refrigerant with no chlorine.
3. What is the unit used to measure static pressure in HVAC ducts?
A. PSI
B. BTU
C. Inches of water column
D. CFH
,Rationale: Static pressure in duct systems is measured in inches of water
column (in. w.c.).
4. A scroll compressor is primarily used in which type of equipment?
A. Absorption chillers
B. Residential and light commercial HVAC systems
C. Industrial ammonia systems
D. Ice machines only
Rationale: Scroll compressors are popular in residential and light
commercial packaged and split systems.
5. The term SEER refers to:
A. Seasonal electrical energy ratio
B. Seasonal Energy Efficiency Ratio
C. Seasonal energy engineering rating
D. Standard efficiency evaluation rating
Rationale: SEER describes cooling efficiency over a season.
6. What is the purpose of a muffler in a refrigeration system?
A. Filter refrigerant
B. Reduce compressor noise and vibration
C. Prevent refrigerant leaks
D. Improve subcooling
Rationale: Mufflers reduce pulsation and noise in compressor discharge
lines.
7. Which component absorbs heat in the refrigeration cycle?
A. Condenser
B. Compressor
C. Metering device
D. Evaporator
Rationale: The evaporator absorbs heat from the conditioned space.
8. A Manual J calculation is used to determine:
, A. Duct sizing
B. Residential load calculation
C. Commercial equipment efficiency
D. Boiler size
Rationale: Manual J determines heating and cooling loads for homes.
9. Which type of system uses water as the heat transfer medium?
A. DX system
B. Hydronic system
C. VRF system
D. Packaged terminal unit
Rationale: Hydronic systems circulate hot or chilled water.
10. The minimum slope for a horizontal condensate drain line is:
A. 0.5%
B. 1% (1/8 inch per foot)
C. 3%
D. No slope needed
Rationale: Condensate drains require a minimum slope of 1/8″ per foot.
11. What is the purpose of a crankcase heater?
A. Prevent condenser flooding
B. Prevent compressor overheating
C. Prevent refrigerant migration into compressor oil
D. Lubricate bearings
Rationale: Heaters keep refrigerant from condensing in oil during off
cycles.
12. A heat pump in heating mode uses which component as the
evaporator?
A. Indoor coil
B. Outdoor coil
C. Reversing valve
Questions And Correct Answers
(Verified Answers) Plus Rationale2026
Q&A| Instant Download Pdf
1. What is the primary purpose of an expansion valve in a refrigeration
cycle?
A. Increase refrigerant pressure
B. Reduce refrigerant pressure and control flow
C. Compress refrigerant vapor
D. Superheat the refrigerant
Rationale: The expansion valve meters refrigerant into the evaporator and
drops its pressure for proper cooling.
2. Which type of refrigerant is commonly classified as an HFC?
A. R-22
B. R-410A
C. R-12
D. R-717
Rationale: R-410A is a hydrofluorocarbon refrigerant with no chlorine.
3. What is the unit used to measure static pressure in HVAC ducts?
A. PSI
B. BTU
C. Inches of water column
D. CFH
,Rationale: Static pressure in duct systems is measured in inches of water
column (in. w.c.).
4. A scroll compressor is primarily used in which type of equipment?
A. Absorption chillers
B. Residential and light commercial HVAC systems
C. Industrial ammonia systems
D. Ice machines only
Rationale: Scroll compressors are popular in residential and light
commercial packaged and split systems.
5. The term SEER refers to:
A. Seasonal electrical energy ratio
B. Seasonal Energy Efficiency Ratio
C. Seasonal energy engineering rating
D. Standard efficiency evaluation rating
Rationale: SEER describes cooling efficiency over a season.
6. What is the purpose of a muffler in a refrigeration system?
A. Filter refrigerant
B. Reduce compressor noise and vibration
C. Prevent refrigerant leaks
D. Improve subcooling
Rationale: Mufflers reduce pulsation and noise in compressor discharge
lines.
7. Which component absorbs heat in the refrigeration cycle?
A. Condenser
B. Compressor
C. Metering device
D. Evaporator
Rationale: The evaporator absorbs heat from the conditioned space.
8. A Manual J calculation is used to determine:
, A. Duct sizing
B. Residential load calculation
C. Commercial equipment efficiency
D. Boiler size
Rationale: Manual J determines heating and cooling loads for homes.
9. Which type of system uses water as the heat transfer medium?
A. DX system
B. Hydronic system
C. VRF system
D. Packaged terminal unit
Rationale: Hydronic systems circulate hot or chilled water.
10. The minimum slope for a horizontal condensate drain line is:
A. 0.5%
B. 1% (1/8 inch per foot)
C. 3%
D. No slope needed
Rationale: Condensate drains require a minimum slope of 1/8″ per foot.
11. What is the purpose of a crankcase heater?
A. Prevent condenser flooding
B. Prevent compressor overheating
C. Prevent refrigerant migration into compressor oil
D. Lubricate bearings
Rationale: Heaters keep refrigerant from condensing in oil during off
cycles.
12. A heat pump in heating mode uses which component as the
evaporator?
A. Indoor coil
B. Outdoor coil
C. Reversing valve
