Airedale SmartCool 11-233kW - Manual (Page 179)

Precision Air Conditioning SmartCool
TM
– D
Precision Air Conditioning
179
Installation, Maintenance and Commissioning Manual :6877419 02/2013
Troubleshooting Indoor Unit
CAUTION ALL work MUST be carried out by technically trained and competent personnel.
The equipment contains live electrical and moving parts, ISOLATE prior to
maintenance or repair work. Ensure electrical lock-off procedures are conducted
FAULT POSSIBLE CAUSE REMEDY / ACTION
Compressor not operating No power to compressor. Check isolator, fuses, MCBs, contactor and
control circuit wiring.
Seized compressor, possibly due to lack of oil,
broken valve. Replace compressor - investigate oil trapping
and general installation.
Defective compressor motor. Check winding resistances - replace
compressor. If burnt out follow burn out
procedure using suction line burn-out drier.
Compressor phase loss. Check 3 phase supply to compressor.
Klixon out 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 - if completely
out evacuate before charging.
Condenser fan motor thermal trip open circuit Investigate and correct.
Noisy compressor Lack of oil. Repair leaks if any, add oil if required but not too
much - remember too much is as bad as too
little. Investigate pipe system and trapping.
Best method to pump down to see if oil can be
encouraged back. If no oil still, drain compressor
and measure in correct quantity.
Expansion valve stuck in open position
(abnormally cold suction Iine). Ensure bulb is tight on suction and superheat is
correct (normally 5 to 6°C).
Replace power assembly or valve as necessary.
Damaged or worn compressor bearing
(excessive knocking). Replace compressor.
Head pressure too high Condenser coil clogged or dirty. Clean condenser coil.
Air or other non-condensable gas in system. Evacuate system and re-charge with new
refrigerant.
Overcharge of refrigerant. Always install new drier before evacuating.
Reclaim excess refrigerant from system (liquid
only).
Head pressure controller faulty. Check fan speed controller - if faulty - replace.
Fan not operating or operating inefficiently. Check motor - if faulty - replace.
Head pressure too low Fan operating too fast in low ambient conditions. Check fan speed controller adjustment - if faulty
- replace.
Compressor short cycles
or LP cut-out operated Dirty filters. Replace.
Dirty or icing evaporator (reduced airflow). Defrost and/or clean. Check gas charge and
expansion valve.
Lack of refrigerant (bubbles in sight glass only
as indication). Check for leaks - repair and recharge system.
Clogged filter drier (pressure / temperature drop
across it). Replace.
Condenser fan running at full speed in winter
(full airflow). Check fan speed controller setting - if faulty -
replace.
Start up problems in very low ambient. Check for low suction pressures on start-up and
fit a low ambient start kit if required, or check
operation of system if already fitted.
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