FAULT POSSIBLE CAUSE REMEDY/ACTION
High room temperature
Damper not operating correctly
Damper jammed in free cooling position
during high ambient conditions.
Compressor(s) not operating. See unit not operating power off - power on.
Compressor(s) not operating efciently.
Important: Check electrical phase rotation.
Fit gauges and investigate.
Heatload too great for system.
High ambient affecting condenser
performance. Investigate design and loads -
clean coil ns.
Low airow Dirty lters - replace.
Control malfunction.
Check transformer/secondary supply -
replace if faulty.
Recalibrate controls if necessary.
Check motor and wiring from controller.
Check sensor not short-circuited - repair/
replace.
Compressor not operating. No power to compressor. Check electrical connectors, isolator,
MPCBs,contactor and control circuit wiring
action. Always investigate fuse/contactor
problem before replacements.
Compressor discharge gas temperature
protection device open.
Allow time to reset. Internal device, change
compressor if it does not reset.
Defective compressor motor. Check windings resistance. If burnt out follow
burn out procedure using drier in suction line.
Always replace the contactor.
Klixon tripped and does not reset. Sometimes it takes up to 4 hours to reset.
Replace compressor if necessary.
Low pressure switch operated (large or
complete loss of refrigerant charge).
Repair leak and recharge system. Evacuate
before charging using good refrigeration
practice.
Fan tripped. Fan motor seized. Free motor or replace.
Fan jammed. Remove obstruction.
Low evaporating temperature. Low refrigerant charge. Recharge refrigerant. (R410A)
Expansion valve faulty or incorrectly set. Replace or adjust expansion valve.
Insufcient airow through evaporator
coil.
Check lter for clogging and fan speed.
Excessively high evaporating
temperature.
Expansion valve faulty. Replace valve.
Troubleshooting
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