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FAN MOTOR - FAULT
Symptom:
Fan motor(s) not operating.
Cause:
Open switch, circuit breaker or fuse. Motor failure. Control thermostat or
defrost mode. Ice accumulation between blade and fan orifice.
Action:
Check for electrical fault – replace motor, fuse or reset circuit breaker. Monitor
for thermostat or defrost operation. Clear ice.
FAN & GUARD – ICE ACCUMULATION
Symptom:
Ice accumulation on fan guard and blades.
Cause
:
Steaming caused by high defrost termination temperature or too many
defrosts. No drain down fan delay. Failed or incorrectly positioned termination
thermostat.
Action:
Adjust or replace termination thermostat. Drain down and snap freeze. Reduce
number of defrosts.
COLD STORE - MOISTURE INGRESS – THIS WILL EXACERBATE ALL SYMPTOMS ABOVE.
Symptom:
Excessive build-up of ice and snow on cooler, ceiling, product and floor.
Cause
:
Failed door seals. Excessive door opening. Failed cold store pressure relief
valve.
Action:
Replace door seals. Review cold store management. Replace cold store
pressure relief valve. Check door heater and consider installing an air curtain
LEAK - ICE BLISTERS
Symptom
:
Multiple leaks on return bend joints.
Cause
:
Moisture in the refrigeration system. Moisture freezes on the brazed joint. With
repeated defrost water builds up, refreezes and expands.
Action
:
Remove the cooler to high ambient location, dehydrate and re braze joints.
Replace
cooler.
CRUSHED TUBES – ICE BALLS
Symptom
:
Crushed and distorted tubes.
Cause
:
Local ice not clearing during defrost. Repeated defrost cycles causes an ice ball
to form and expand.
Action
:
Relocate defrost termination probe to remaining ice spot. Regular inspection. In
severe cases, disconnect circuit with damaged tube or replace coil.
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