1. What is the primary function of a refrigeration cycle?
A. To produce heat
B. To transfer heat from a low-temperature area to a high-temperature area
C. To increase pressure in a closed system
D. To maintain constant humidity
Answer: B
Explanation: The refrigeration cycle absorbs heat from a space (low
temperature) and rejects it to the outside (high temperature) through
compression and expansion processes.
2. In the vapor compression refrigeration cycle, where does the refrigerant
absorb heat?
A. Condenser
B. Compressor
C. Evaporator
D. Metering device
Answer: C
Explanation: The evaporator is the heat absorption component. The refrigerant
evaporates at low pressure and absorbs heat from the conditioned space.
3. What is the typical superheat range recommended at the evaporator
outlet?
A. 0–2°F
B. 8–12°F
C. 20–30°F
D. 30–40°F
,Answer: B
Explanation: 8–12°F of superheat ensures that only vapor enters the
compressor, protecting it from liquid slugging.
4. Which refrigerant is being phased out due to high ozone depletion
potential (ODP)?
A. R-134a
B. R-22
C. R-410A
D. R-1234yf
Answer: B
Explanation: R-22 (HCFC-22) is phased out under the Montreal Protocol due
to its ozone-depleting chlorine content.
5. According to EPA Section 608, which certification type is required for
servicing high-pressure appliances like R-410A systems?
A. Type I
B. Type II
C. Type III
D. Universal
Answer: B
Explanation: Type II covers high-pressure appliances, while Type I is for small
appliances, Type III for low-pressure chillers, and Universal covers all.
6. What is the main function of the compressor in a refrigeration system?
A. To remove moisture from refrigerant
B. To raise refrigerant pressure and temperature
C. To cool refrigerant to condensation point
D. To meter refrigerant into evaporator
Answer: B
Explanation: The compressor compresses low-pressure vapor to high-pressure
vapor, enabling condensation at higher temperatures.
,7. What does SEER stand for in HVAC systems?
A. Seasonal Energy Efficiency Ratio
B. Standard Energy Exchange Rating
C. Seasonal Electrical Energy Requirement
D. System Efficiency Evaluation Ratio
Answer: A
Explanation: SEER = cooling output (BTU) ÷ electrical energy input (Wh)
over a season. Higher SEER means higher efficiency.
8. What is the maximum allowable pressure drop in a supply duct
according to SMACNA standards?
A. 0.05 in. w.c.
B. 0.10 in. w.c.
C. 0.25 in. w.c.
D. 0.50 in. w.c.
Answer: C
Explanation: SMACNA recommends that duct systems be designed with a
maximum pressure drop of around 0.25 in. w.c. per 100 feet for efficiency.
9. What is the purpose of a TXV (Thermostatic Expansion Valve)?
A. To increase refrigerant pressure
B. To control superheat at evaporator outlet
C. To act as a safety pressure relief
D. To remove non-condensables
Answer: B
Explanation: The TXV regulates refrigerant flow into the evaporator based on
superheat, ensuring stable operation.
10. What does the acronym “CFM” stand for in HVAC airflow?
, A. Cubic Feet per Meter
B. Cubic Feet per Minute
C. Cooling Fan Measurement
D. Control Flow Management
Answer: B
Explanation: CFM measures air volume flow rate, a critical parameter for duct
and equipment sizing.
11. Which component in the refrigeration cycle rejects heat to the outdoor
air?
A. Evaporator
B. Condenser
C. Expansion valve
D. Suction line
Answer: B
Explanation: The condenser rejects absorbed heat to the outside by condensing
high-pressure vapor into liquid.
12. What is the primary purpose of an accumulator in a refrigeration
system?
A. To increase refrigerant velocity
B. To prevent liquid refrigerant from entering the compressor
C. To increase compressor efficiency
D. To act as a muffler
Answer: B
Explanation: Accumulators protect compressors from liquid slugging by
holding excess liquid refrigerant.
13. In psychrometrics, which property represents the ratio of water vapor
mass to dry air mass?
A. Specific humidity
B. Relative humidity
C. Enthalpy
D. Dew point
A. To produce heat
B. To transfer heat from a low-temperature area to a high-temperature area
C. To increase pressure in a closed system
D. To maintain constant humidity
Answer: B
Explanation: The refrigeration cycle absorbs heat from a space (low
temperature) and rejects it to the outside (high temperature) through
compression and expansion processes.
2. In the vapor compression refrigeration cycle, where does the refrigerant
absorb heat?
A. Condenser
B. Compressor
C. Evaporator
D. Metering device
Answer: C
Explanation: The evaporator is the heat absorption component. The refrigerant
evaporates at low pressure and absorbs heat from the conditioned space.
3. What is the typical superheat range recommended at the evaporator
outlet?
A. 0–2°F
B. 8–12°F
C. 20–30°F
D. 30–40°F
,Answer: B
Explanation: 8–12°F of superheat ensures that only vapor enters the
compressor, protecting it from liquid slugging.
4. Which refrigerant is being phased out due to high ozone depletion
potential (ODP)?
A. R-134a
B. R-22
C. R-410A
D. R-1234yf
Answer: B
Explanation: R-22 (HCFC-22) is phased out under the Montreal Protocol due
to its ozone-depleting chlorine content.
5. According to EPA Section 608, which certification type is required for
servicing high-pressure appliances like R-410A systems?
A. Type I
B. Type II
C. Type III
D. Universal
Answer: B
Explanation: Type II covers high-pressure appliances, while Type I is for small
appliances, Type III for low-pressure chillers, and Universal covers all.
6. What is the main function of the compressor in a refrigeration system?
A. To remove moisture from refrigerant
B. To raise refrigerant pressure and temperature
C. To cool refrigerant to condensation point
D. To meter refrigerant into evaporator
Answer: B
Explanation: The compressor compresses low-pressure vapor to high-pressure
vapor, enabling condensation at higher temperatures.
,7. What does SEER stand for in HVAC systems?
A. Seasonal Energy Efficiency Ratio
B. Standard Energy Exchange Rating
C. Seasonal Electrical Energy Requirement
D. System Efficiency Evaluation Ratio
Answer: A
Explanation: SEER = cooling output (BTU) ÷ electrical energy input (Wh)
over a season. Higher SEER means higher efficiency.
8. What is the maximum allowable pressure drop in a supply duct
according to SMACNA standards?
A. 0.05 in. w.c.
B. 0.10 in. w.c.
C. 0.25 in. w.c.
D. 0.50 in. w.c.
Answer: C
Explanation: SMACNA recommends that duct systems be designed with a
maximum pressure drop of around 0.25 in. w.c. per 100 feet for efficiency.
9. What is the purpose of a TXV (Thermostatic Expansion Valve)?
A. To increase refrigerant pressure
B. To control superheat at evaporator outlet
C. To act as a safety pressure relief
D. To remove non-condensables
Answer: B
Explanation: The TXV regulates refrigerant flow into the evaporator based on
superheat, ensuring stable operation.
10. What does the acronym “CFM” stand for in HVAC airflow?
, A. Cubic Feet per Meter
B. Cubic Feet per Minute
C. Cooling Fan Measurement
D. Control Flow Management
Answer: B
Explanation: CFM measures air volume flow rate, a critical parameter for duct
and equipment sizing.
11. Which component in the refrigeration cycle rejects heat to the outdoor
air?
A. Evaporator
B. Condenser
C. Expansion valve
D. Suction line
Answer: B
Explanation: The condenser rejects absorbed heat to the outside by condensing
high-pressure vapor into liquid.
12. What is the primary purpose of an accumulator in a refrigeration
system?
A. To increase refrigerant velocity
B. To prevent liquid refrigerant from entering the compressor
C. To increase compressor efficiency
D. To act as a muffler
Answer: B
Explanation: Accumulators protect compressors from liquid slugging by
holding excess liquid refrigerant.
13. In psychrometrics, which property represents the ratio of water vapor
mass to dry air mass?
A. Specific humidity
B. Relative humidity
C. Enthalpy
D. Dew point
