Alberta Refrigeration And Air Conditioning
Mechanic Apprenticeship Certification
Exam Questions And Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A | Instant Download Pdf
1. Which refrigerant is considered an ozone-depleting substance?
A) R-410A
B) R-134a
C) R-22
D) R-407C
Rationale: R-22 is a hydrochlorofluorocarbon (HCFC) that contributes
to ozone depletion.
2. What is the purpose of the expansion device in a refrigeration system?
A) Increase refrigerant pressure
B) Heat the refrigerant
C) Reduce refrigerant pressure and control flow
D) Compress the refrigerant
Rationale: The expansion device lowers refrigerant pressure to allow
proper heat absorption in the evaporator.
3. In a vapor-compression system, the component that removes heat
from the refrigerant and rejects it to the atmosphere is the:
A) Evaporator
B) Expansion valve
, C) Compressor
D) Condenser
Rationale: The condenser releases heat absorbed in the evaporator
to the surrounding air or water.
4. A subcooling measurement is taken to:
A) Determine suction pressure
B) Verify the refrigerant is fully condensed
C) Measure superheat
D) Check compressor efficiency
Rationale: Subcooling ensures the refrigerant is completely in liquid
state before reaching the expansion device.
5. Which gas is commonly used for leak detection in HVAC systems?
A) Oxygen
B) Nitrogen
C) Carbon monoxide
D) Helium
Rationale: Nitrogen is inert and safe for pressurizing systems to check
for leaks.
6. The primary function of a compressor is to:
A) Evaporate refrigerant
B) Condense refrigerant
C) Increase refrigerant pressure and temperature
D) Expand refrigerant
Rationale: Compressors raise the pressure and temperature of
refrigerant vapor to allow heat rejection in the condenser.
7. What is the typical operating pressure of R-410A in residential air
conditioning systems?
A) 50–100 psi
B) 100–150 psi
, C) 200–400 psi
D) 450–600 psi
Rationale: R-410A operates at higher pressures than R-22, often in
the 200–400 psi range for residential units.
8. Which type of compressor uses pistons to compress refrigerant?
A) Scroll
B) Reciprocating
C) Centrifugal
D) Rotary
Rationale: Reciprocating compressors use pistons in cylinders to
compress refrigerant.
9. In refrigeration, superheat refers to:
A) Refrigerant below its boiling point
B) Temperature of refrigerant vapor above its saturation temperature
C) Refrigerant condensed in the condenser
D) Refrigerant at expansion valve inlet
Rationale: Superheat measures how much vapor temperature is
above its saturation point at the evaporator outlet.
10. Which of the following is a safety device installed to prevent
overpressure in a refrigeration system?
A) Thermostat
B) Filter drier
C) Sight glass
D) Relief valve
Rationale: Relief valves protect equipment from excessive pressure
by releasing refrigerant when limits are exceeded.
11. What is the primary purpose of a filter-drier in a refrigeration
system?
A) Increase refrigerant pressure
Mechanic Apprenticeship Certification
Exam Questions And Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A | Instant Download Pdf
1. Which refrigerant is considered an ozone-depleting substance?
A) R-410A
B) R-134a
C) R-22
D) R-407C
Rationale: R-22 is a hydrochlorofluorocarbon (HCFC) that contributes
to ozone depletion.
2. What is the purpose of the expansion device in a refrigeration system?
A) Increase refrigerant pressure
B) Heat the refrigerant
C) Reduce refrigerant pressure and control flow
D) Compress the refrigerant
Rationale: The expansion device lowers refrigerant pressure to allow
proper heat absorption in the evaporator.
3. In a vapor-compression system, the component that removes heat
from the refrigerant and rejects it to the atmosphere is the:
A) Evaporator
B) Expansion valve
, C) Compressor
D) Condenser
Rationale: The condenser releases heat absorbed in the evaporator
to the surrounding air or water.
4. A subcooling measurement is taken to:
A) Determine suction pressure
B) Verify the refrigerant is fully condensed
C) Measure superheat
D) Check compressor efficiency
Rationale: Subcooling ensures the refrigerant is completely in liquid
state before reaching the expansion device.
5. Which gas is commonly used for leak detection in HVAC systems?
A) Oxygen
B) Nitrogen
C) Carbon monoxide
D) Helium
Rationale: Nitrogen is inert and safe for pressurizing systems to check
for leaks.
6. The primary function of a compressor is to:
A) Evaporate refrigerant
B) Condense refrigerant
C) Increase refrigerant pressure and temperature
D) Expand refrigerant
Rationale: Compressors raise the pressure and temperature of
refrigerant vapor to allow heat rejection in the condenser.
7. What is the typical operating pressure of R-410A in residential air
conditioning systems?
A) 50–100 psi
B) 100–150 psi
, C) 200–400 psi
D) 450–600 psi
Rationale: R-410A operates at higher pressures than R-22, often in
the 200–400 psi range for residential units.
8. Which type of compressor uses pistons to compress refrigerant?
A) Scroll
B) Reciprocating
C) Centrifugal
D) Rotary
Rationale: Reciprocating compressors use pistons in cylinders to
compress refrigerant.
9. In refrigeration, superheat refers to:
A) Refrigerant below its boiling point
B) Temperature of refrigerant vapor above its saturation temperature
C) Refrigerant condensed in the condenser
D) Refrigerant at expansion valve inlet
Rationale: Superheat measures how much vapor temperature is
above its saturation point at the evaporator outlet.
10. Which of the following is a safety device installed to prevent
overpressure in a refrigeration system?
A) Thermostat
B) Filter drier
C) Sight glass
D) Relief valve
Rationale: Relief valves protect equipment from excessive pressure
by releasing refrigerant when limits are exceeded.
11. What is the primary purpose of a filter-drier in a refrigeration
system?
A) Increase refrigerant pressure
