Quantum 270-11AC3-134 User Manual
Owner’s Manual
Quantum Energy Technologies
Document number: QDC0030PD-11 Page 32 of 40
A.2: Thermal Cut Out Trips Off Repeatedly
Probable Cause
Test / Observation
Action
1. Low refrigerant charge.
Check refrigerant charge.
Test for possible leak in the refrigeration circuit.
Test for possible leak in the refrigeration circuit.
Top up refrigerant or re-charge.
Repair leak, or if not repairable, contact
QUANTUM service.
Repair leak, or if not repairable, contact
QUANTUM service.
2. High refrigerant charge.
Check refrigerant charge. Over charge causes high current
draw and excessive head pressure resulting in a hot
compressor.
draw and excessive head pressure resulting in a hot
compressor.
Correct the refrigerant charge.
3. Incorrect voltage and frequency.
Check power supply quality while unit is running.
Rectify improper power supply or shut off
system and report to the client.
system and report to the client.
4. Compressor runs hot:
Internal leakage.
High suction superheat.
High current draw.
High head pressure.
Internal leakage.
High suction superheat.
High current draw.
High head pressure.
Thermal Cut Out faulty.
De-ice solenoid remains open.
Observe compressor operation: pressure delivery, noise.
Check liquid cooling system for faulty parts or blocked
capillary etc. Check super heat setting on TX valve and TX
valve operation.
Check for refrigerant over charge, compressor winding
resistance or mechanical fault in the compressor rotors or
valves.
Check for high condensing temperature due to: I) faulty water
thermostat / digital controller, which does not cut off or II)
restriction, blockage in condenser or III) poor heat transfer to
tank - possibly bonding of condenser coil to tank has failed.
Check for correct operation of Digital Controller.
Check for faulty de-ice solenoid parts or thermostat. Check for
incorrect wiring.
Check liquid cooling system for faulty parts or blocked
capillary etc. Check super heat setting on TX valve and TX
valve operation.
Check for refrigerant over charge, compressor winding
resistance or mechanical fault in the compressor rotors or
valves.
Check for high condensing temperature due to: I) faulty water
thermostat / digital controller, which does not cut off or II)
restriction, blockage in condenser or III) poor heat transfer to
tank - possibly bonding of condenser coil to tank has failed.
Check for correct operation of Digital Controller.
Check for faulty de-ice solenoid parts or thermostat. Check for
incorrect wiring.
If faulty, replace compressor and filter.
Replace liquid injection parts if faulty.
Adjust superheat or if TX valve faulty
replace TX valve.
Adjust gas charge if needed or replace
compressor if it is faulty.
I) Replace faulty water thermostat / digital
controller. II) If restriction is not
removable replace blocked part. III)
Replace tank.
Replace Digital Controller if faulty.
Replace faulty de-ice parts. Correct
wiring.
Replace liquid injection parts if faulty.
Adjust superheat or if TX valve faulty
replace TX valve.
Adjust gas charge if needed or replace
compressor if it is faulty.
I) Replace faulty water thermostat / digital
controller. II) If restriction is not
removable replace blocked part. III)
Replace tank.
Replace Digital Controller if faulty.
Replace faulty de-ice parts. Correct
wiring.
5. Poor oil return to compressor.
Check for oil traps in the tubes between evaporator and tank.
Rectify installation defects