ESCO Light Commercial Refrigeration
(Refrigeration Systems)
Comprehensive Resource To Help You Ace 2026-2027
Includes Frequently Tested Questions With ELABORATED
100% Correct COMPLETE SOLUTIONS Guaranteed Pass First
Attempt!! Current Update!!
1. When a compressor service valve is back-seated, which port is closed?
A. Suction port
B. Discharge port
C. Service port
D. Equalizing port
Correct Answer: C. Service port
2. The purpose of a low ambient control is to regulate:
A. Evaporator temperature
B. Suction pressure
C. Head pressure
D. Oil pressure
Correct Answer: C. Head pressure
3. In a direct expansion (dry type) evaporator, refrigerant should completely boil off near the
end of the coil to:
A. Prevent freezing
B. Increase pressure
C. Operate at high efficiency
D. Reduce compressor load
Correct Answer: C. Operate at high efficiency
,4. The difference between the boiling temperature of refrigerant in the evaporator and the
temperature at the outlet is called:
A. Subcooling
B. Compression ratio
C. Evaporator superheat
D. Condensing temperature
Correct Answer: C. Evaporator superheat
5. An expansion device stuck open will most likely cause:
A. Starved evaporator
B. High superheat
C. Flooded evaporator
D. Low head pressure
Correct Answer: C. Flooded evaporator
6. When measuring superheat on a system with a long suction line, pressure should be
measured at the:
A. Evaporator outlet
B. Liquid line
C. Compressor inlet
D. Condenser outlet
Correct Answer: C. Compressor inlet
7. Superheat measurements should be taken when the system is:
A. Just started
B. Under low load
C. At design operating conditions
D. In defrost mode
Correct Answer: C. At design operating conditions
,8. If one circuit in a multi-circuit evaporator has higher superheat than others, the likely cause
is:
A. Overcharge
B. Blocked distributor
C. Dirty condenser
D. Low airflow
Correct Answer: B. Blocked distributor
9. A TXV with an external equalizer is used on evaporators with:
A. Low airflow
B. High pressure drop
C. High superheat
D. Low temperature
Correct Answer: B. High pressure drop
10. Dry type evaporators operate most efficiently with superheat set at approximately:
A. 2–5°F
B. 5–7°F
C. 8–12°F
D. 15–20°F
Correct Answer: C. 8–12°F
11. If an evaporator has normal superheat but poor cooling, the likely cause is:
A. Undercharge
B. Overcharge
C. Low airflow
D. Dirty evaporator
Correct Answer: B. Overcharge
, 12. After adjusting superheat, how long should a technician wait before making another
adjustment?
A. 1–2 minutes
B. 5 minutes
C. 10–15 minutes
D. 30 minutes
Correct Answer: C. 10–15 minutes
13. Low temperature evaporators must be:
A. Pressurized
B. Insulated
C. Defrosted periodically
D. Oversized
Correct Answer: C. Defrosted periodically
14. Flooded evaporators use which device to maintain liquid level?
A. TXV
B. Capillary tube
C. Low-side float
D. EPR valve
Correct Answer: C. Low-side float
15. A properly functioning condenser will:
A. Subcool first, then de-superheat
B. De-superheat first, then subcool
C. Compress refrigerant
D. Evaporate refrigerant
Correct Answer: B. De-superheat first, then subcool
(Refrigeration Systems)
Comprehensive Resource To Help You Ace 2026-2027
Includes Frequently Tested Questions With ELABORATED
100% Correct COMPLETE SOLUTIONS Guaranteed Pass First
Attempt!! Current Update!!
1. When a compressor service valve is back-seated, which port is closed?
A. Suction port
B. Discharge port
C. Service port
D. Equalizing port
Correct Answer: C. Service port
2. The purpose of a low ambient control is to regulate:
A. Evaporator temperature
B. Suction pressure
C. Head pressure
D. Oil pressure
Correct Answer: C. Head pressure
3. In a direct expansion (dry type) evaporator, refrigerant should completely boil off near the
end of the coil to:
A. Prevent freezing
B. Increase pressure
C. Operate at high efficiency
D. Reduce compressor load
Correct Answer: C. Operate at high efficiency
,4. The difference between the boiling temperature of refrigerant in the evaporator and the
temperature at the outlet is called:
A. Subcooling
B. Compression ratio
C. Evaporator superheat
D. Condensing temperature
Correct Answer: C. Evaporator superheat
5. An expansion device stuck open will most likely cause:
A. Starved evaporator
B. High superheat
C. Flooded evaporator
D. Low head pressure
Correct Answer: C. Flooded evaporator
6. When measuring superheat on a system with a long suction line, pressure should be
measured at the:
A. Evaporator outlet
B. Liquid line
C. Compressor inlet
D. Condenser outlet
Correct Answer: C. Compressor inlet
7. Superheat measurements should be taken when the system is:
A. Just started
B. Under low load
C. At design operating conditions
D. In defrost mode
Correct Answer: C. At design operating conditions
,8. If one circuit in a multi-circuit evaporator has higher superheat than others, the likely cause
is:
A. Overcharge
B. Blocked distributor
C. Dirty condenser
D. Low airflow
Correct Answer: B. Blocked distributor
9. A TXV with an external equalizer is used on evaporators with:
A. Low airflow
B. High pressure drop
C. High superheat
D. Low temperature
Correct Answer: B. High pressure drop
10. Dry type evaporators operate most efficiently with superheat set at approximately:
A. 2–5°F
B. 5–7°F
C. 8–12°F
D. 15–20°F
Correct Answer: C. 8–12°F
11. If an evaporator has normal superheat but poor cooling, the likely cause is:
A. Undercharge
B. Overcharge
C. Low airflow
D. Dirty evaporator
Correct Answer: B. Overcharge
, 12. After adjusting superheat, how long should a technician wait before making another
adjustment?
A. 1–2 minutes
B. 5 minutes
C. 10–15 minutes
D. 30 minutes
Correct Answer: C. 10–15 minutes
13. Low temperature evaporators must be:
A. Pressurized
B. Insulated
C. Defrosted periodically
D. Oversized
Correct Answer: C. Defrosted periodically
14. Flooded evaporators use which device to maintain liquid level?
A. TXV
B. Capillary tube
C. Low-side float
D. EPR valve
Correct Answer: C. Low-side float
15. A properly functioning condenser will:
A. Subcool first, then de-superheat
B. De-superheat first, then subcool
C. Compress refrigerant
D. Evaporate refrigerant
Correct Answer: B. De-superheat first, then subcool
