COMMERCIAL REFRIGERATION TECHNICIAN EXAM
PRACTICE TEST COMPLETE 100 QUESTIONS AND
CORRECT DETAILED ANSWERS (VERIFIED
ANSWERS) |ALREADY GRADED A+||BRAND NEW
VERSION!!
1. What is the primary purpose of a TXV (Thermostatic Expansion Valve)?
A. Increase suction pressure
B. Lower condenser temperature
✔ C. Regulate refrigerant flow into the evaporator
D. Measure superheat
The TXV meters refrigerant based on evaporator load and maintains proper
superheat.
2. What does a low superheat reading typically indicate?
A. System undercharged
✔ B. Flooded evaporator
C. TXV stuck closed
D. Air restriction
Low superheat shows too much refrigerant in evaporator → risk of liquid return.
3. What is the usual state of refrigerant leaving the condenser?
A. Superheated vapor
✔ B. Subcooled liquid
C. Saturated vapor
D. Flash gas
Condensers reject heat until refrigerant becomes a subcooled liquid.
,4. A receiver is located:
✔ A. Downstream of the condenser
B. Upstream of the compressor
C. Between the evaporator and TXV
D. Inside suction line
Holds liquid refrigerant after condensation.
5. What condition is indicated by high head pressure?
A. Undercharge
✔ B. Dirty condenser
C. Low air flow across evaporator
D. Failed TXV bulb
Heat rejection is reduced → head pressure rises.
6. Flash gas in the liquid line results in:
✔ A. Starving evaporator
B. High suction pressure
C. Oil foaming
D. Compressor overheating
Gas bubbles reduce refrigerant entering evaporator.
7. What protects the compressor from refrigerant floodback?
A. Liquid receiver
B. Discharge line muffler
✔ C. Accumulator
D. Sight glass
Accumulators trap liquid preventing damage.
8. A sight glass showing constant bubbles often means:
A. System overcharged
✔ B. Moisture or low charge
C. TXV wide open
, D. Evaporator restriction
Indicates refrigerant flash due to moisture or shortage.
9. When replacing a filter-drier, what must be done?
A. Bypass vacuuming
✔ B. Purge nitrogen while brazing
C. Overcharge system
D. Increase superheat
Prevents oxidation and internal debris contamination.
10. The best way to check moisture in a system is:
✔ A. Use sight glass moisture indicator
B. Check superheat
C. Feel suction line
D. Inspect oil level
Chemical indicators detect moisture presence.
11. Which tool measures percentage of oil vs. refrigerant?
A. Micron gauge
B. Volt meter
✔ C. Oil/refrigerant hydrometer
D. Sling psychrometer
Specific gravity testing determines oil condition.
12. Common evaporator defrost method in freezers:
A. Ambient air
✔ B. Electric heaters
C. Suction pressure rise
D. TXV bypass
Electric defrost is typical in commercial low-temp systems.
13. Head pressure control is required in low ambient temps to:
PRACTICE TEST COMPLETE 100 QUESTIONS AND
CORRECT DETAILED ANSWERS (VERIFIED
ANSWERS) |ALREADY GRADED A+||BRAND NEW
VERSION!!
1. What is the primary purpose of a TXV (Thermostatic Expansion Valve)?
A. Increase suction pressure
B. Lower condenser temperature
✔ C. Regulate refrigerant flow into the evaporator
D. Measure superheat
The TXV meters refrigerant based on evaporator load and maintains proper
superheat.
2. What does a low superheat reading typically indicate?
A. System undercharged
✔ B. Flooded evaporator
C. TXV stuck closed
D. Air restriction
Low superheat shows too much refrigerant in evaporator → risk of liquid return.
3. What is the usual state of refrigerant leaving the condenser?
A. Superheated vapor
✔ B. Subcooled liquid
C. Saturated vapor
D. Flash gas
Condensers reject heat until refrigerant becomes a subcooled liquid.
,4. A receiver is located:
✔ A. Downstream of the condenser
B. Upstream of the compressor
C. Between the evaporator and TXV
D. Inside suction line
Holds liquid refrigerant after condensation.
5. What condition is indicated by high head pressure?
A. Undercharge
✔ B. Dirty condenser
C. Low air flow across evaporator
D. Failed TXV bulb
Heat rejection is reduced → head pressure rises.
6. Flash gas in the liquid line results in:
✔ A. Starving evaporator
B. High suction pressure
C. Oil foaming
D. Compressor overheating
Gas bubbles reduce refrigerant entering evaporator.
7. What protects the compressor from refrigerant floodback?
A. Liquid receiver
B. Discharge line muffler
✔ C. Accumulator
D. Sight glass
Accumulators trap liquid preventing damage.
8. A sight glass showing constant bubbles often means:
A. System overcharged
✔ B. Moisture or low charge
C. TXV wide open
, D. Evaporator restriction
Indicates refrigerant flash due to moisture or shortage.
9. When replacing a filter-drier, what must be done?
A. Bypass vacuuming
✔ B. Purge nitrogen while brazing
C. Overcharge system
D. Increase superheat
Prevents oxidation and internal debris contamination.
10. The best way to check moisture in a system is:
✔ A. Use sight glass moisture indicator
B. Check superheat
C. Feel suction line
D. Inspect oil level
Chemical indicators detect moisture presence.
11. Which tool measures percentage of oil vs. refrigerant?
A. Micron gauge
B. Volt meter
✔ C. Oil/refrigerant hydrometer
D. Sling psychrometer
Specific gravity testing determines oil condition.
12. Common evaporator defrost method in freezers:
A. Ambient air
✔ B. Electric heaters
C. Suction pressure rise
D. TXV bypass
Electric defrost is typical in commercial low-temp systems.
13. Head pressure control is required in low ambient temps to:
