Test Bank For
Commercial Refrigeration for Air
Conditioning Technicians 4th Edition
by Dick Wirz
Commercial Refrigeration Practice Questions (with
Solutions)
1. What component in a refrigeration system removes heat from the refrigerated space?
A. Condenser
B. Evaporator
C. Compressor
D. Receiver
Answer: B – The evaporator absorbs heat from inside the refrigerated space.
2. The purpose of the compressor in a refrigeration system is to:
A. Absorb heat
B. Increase refrigerant pressure
C. Expand refrigerant
D. Filter the air
Answer: B – The compressor raises the pressure and temperature of the refrigerant
vapor.
3. Which of the following is a common refrigerant used in commercial systems?
A. R‑22
B. R‑410A
C. R‑744 (CO₂)
D. All of the above
Answer: D – These are all used in commercial systems, with R‑744 becoming more
common for natural refrigerant applications.
4. In a refrigeration cycle, the condenser’s main function is to:
A. Lower refrigerant pressure
B. Reject heat to the surroundings
C. Store liquid refrigerant
, D. Increase humidity
Answer: B – The condenser releases heat from the refrigerant to the outside
environment.
5. A thermostatic expansion valve (TXV) is used to:
A. Control refrigerant flow into the evaporator
B. Filter liquid refrigerant
C. Compress refrigerant
D. Absorb heat
Answer: A – The TXV ensures refrigerant enters the evaporator at the correct rate.
6. What is “superheat” in refrigeration?
A. Temperature of refrigerant below saturation
B. Temperature above saturation at evaporator outlet
C. Pressure difference in compressor
D. Condenser fan speed
Answer: B – Superheat refers to how much the refrigerant vapor is heated above its
saturation temperature at the evaporator outlet.
7. What tool is typically used to measure system pressures in a commercial refrigeration
unit?
A. Multimeter
B. Refrigeration gauges (manifold)
C. Thermocouple
D. Tachometer
Answer: B – Refrigeration gauges measure low‑side and high‑side pressures.
8. Which of the following indicates a possible low refrigerant charge?
A. High suction pressure
B. Low superheat
C. Frost on evaporator coil
D. Compressor overheating
Answer: C – Frost or ice buildup on the evaporator can indicate low refrigerant.
9. A receiver in a refrigeration system is used to:
A. Store liquid refrigerant
B. Filter moisture
C. Pump refrigerant
D. Measure temperature
Answer: A – The receiver holds excess liquid refrigerant.
10.The term “subcooling” refers to:
A. Cooling of refrigerant below its boiling point
B. Heating of the compressor discharge line
C. Increasing refrigerant pressure
D. The evaporator coil picking up heat
Answer: A – Subcooling is lowering liquid refrigerant below its saturation (boiling)
temperature.
11.What safety device protects a compressor from excessive current?
A. High‑pressure switch
, B. Low‑pressure switch
C. Thermal overload protector
D. Sight glass
Answer: C – Thermal overload protects the compressor from overheating.
12.The primary cause of liquid slugging in a compressor is:
A. Too much oil
B. Refrigerant returning as liquid
C. Too high suction pressure
D. Dirty air filters
Answer: B – Liquid entering the compressor can cause slugging and damage.
13.Heat reclaim in refrigeration systems is used to:
A. Increase cooling efficiency
B. Use rejected heat for other purposes
C. Reduce evaporation rate
D. Decrease thermostat sensitivity
Answer: B – Heat reclaim captures waste heat for water heating or space heating.
14.Which meter device adjusts refrigerant flow based on load conditions?
A. Fixed orifice
B. Capillary tube
C. Thermostatic expansion valve (TXV)
D. Strainer
Answer: C – The TXV regulates flow with changing load.
15.A common sign of low airflow across the evaporator coil is:
A. High discharge temperature
B. Frost on the suction line
C. High head pressure
D. Uneven cooling
Answer: D – Reduced airflow often leads to uneven temperatures in the refrigerated
space.
16.What is the main purpose of the liquid line filter‑drier?
A. Compress refrigerant
B. Remove moisture and debris
C. Increase refrigerant flow
D. Control temperature
Answer: B – The filter‑drier removes moisture and particulate contamination from the
system.
17.Which component is responsible for rejecting heat to the ambient air?
A. Evaporator
B. Condenser
C. Expansion valve
Commercial Refrigeration for Air
Conditioning Technicians 4th Edition
by Dick Wirz
Commercial Refrigeration Practice Questions (with
Solutions)
1. What component in a refrigeration system removes heat from the refrigerated space?
A. Condenser
B. Evaporator
C. Compressor
D. Receiver
Answer: B – The evaporator absorbs heat from inside the refrigerated space.
2. The purpose of the compressor in a refrigeration system is to:
A. Absorb heat
B. Increase refrigerant pressure
C. Expand refrigerant
D. Filter the air
Answer: B – The compressor raises the pressure and temperature of the refrigerant
vapor.
3. Which of the following is a common refrigerant used in commercial systems?
A. R‑22
B. R‑410A
C. R‑744 (CO₂)
D. All of the above
Answer: D – These are all used in commercial systems, with R‑744 becoming more
common for natural refrigerant applications.
4. In a refrigeration cycle, the condenser’s main function is to:
A. Lower refrigerant pressure
B. Reject heat to the surroundings
C. Store liquid refrigerant
, D. Increase humidity
Answer: B – The condenser releases heat from the refrigerant to the outside
environment.
5. A thermostatic expansion valve (TXV) is used to:
A. Control refrigerant flow into the evaporator
B. Filter liquid refrigerant
C. Compress refrigerant
D. Absorb heat
Answer: A – The TXV ensures refrigerant enters the evaporator at the correct rate.
6. What is “superheat” in refrigeration?
A. Temperature of refrigerant below saturation
B. Temperature above saturation at evaporator outlet
C. Pressure difference in compressor
D. Condenser fan speed
Answer: B – Superheat refers to how much the refrigerant vapor is heated above its
saturation temperature at the evaporator outlet.
7. What tool is typically used to measure system pressures in a commercial refrigeration
unit?
A. Multimeter
B. Refrigeration gauges (manifold)
C. Thermocouple
D. Tachometer
Answer: B – Refrigeration gauges measure low‑side and high‑side pressures.
8. Which of the following indicates a possible low refrigerant charge?
A. High suction pressure
B. Low superheat
C. Frost on evaporator coil
D. Compressor overheating
Answer: C – Frost or ice buildup on the evaporator can indicate low refrigerant.
9. A receiver in a refrigeration system is used to:
A. Store liquid refrigerant
B. Filter moisture
C. Pump refrigerant
D. Measure temperature
Answer: A – The receiver holds excess liquid refrigerant.
10.The term “subcooling” refers to:
A. Cooling of refrigerant below its boiling point
B. Heating of the compressor discharge line
C. Increasing refrigerant pressure
D. The evaporator coil picking up heat
Answer: A – Subcooling is lowering liquid refrigerant below its saturation (boiling)
temperature.
11.What safety device protects a compressor from excessive current?
A. High‑pressure switch
, B. Low‑pressure switch
C. Thermal overload protector
D. Sight glass
Answer: C – Thermal overload protects the compressor from overheating.
12.The primary cause of liquid slugging in a compressor is:
A. Too much oil
B. Refrigerant returning as liquid
C. Too high suction pressure
D. Dirty air filters
Answer: B – Liquid entering the compressor can cause slugging and damage.
13.Heat reclaim in refrigeration systems is used to:
A. Increase cooling efficiency
B. Use rejected heat for other purposes
C. Reduce evaporation rate
D. Decrease thermostat sensitivity
Answer: B – Heat reclaim captures waste heat for water heating or space heating.
14.Which meter device adjusts refrigerant flow based on load conditions?
A. Fixed orifice
B. Capillary tube
C. Thermostatic expansion valve (TXV)
D. Strainer
Answer: C – The TXV regulates flow with changing load.
15.A common sign of low airflow across the evaporator coil is:
A. High discharge temperature
B. Frost on the suction line
C. High head pressure
D. Uneven cooling
Answer: D – Reduced airflow often leads to uneven temperatures in the refrigerated
space.
16.What is the main purpose of the liquid line filter‑drier?
A. Compress refrigerant
B. Remove moisture and debris
C. Increase refrigerant flow
D. Control temperature
Answer: B – The filter‑drier removes moisture and particulate contamination from the
system.
17.Which component is responsible for rejecting heat to the ambient air?
A. Evaporator
B. Condenser
C. Expansion valve
