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T-368
4–32
AL12
EVAPORATOR FAN 2 IP
Cause:
Alarm 12 is triggered when configured for single evap operation and KB10 sensed high.
Component
Evaporator Fan 2
Troubleshooting
The unit will suspend probe check diagnostic logic and disable the probe
check portion of defrost cycle.
Corrective Action
AL11 is triggered off when KB10 sensed low.
AL15
LOSS OF COOLING
Cause:
AL15 is triggered 30 minutes after the completion of a controller initiated probe check defrost if
Supply Temperature is more than 0.25°C (0.45°F) above set point. Refer to
.
Component
Refrigerant Level
Troubleshooting
Power cycle the unit.
Corrective Action
Refer to Refrigerant Charge,
Power cycle the unit.
AL20
CONTROL CONTACTOR FUSE (F3)
Cause:
Control power fuse (F3A or F3B) is open.
Component
Check F3A, if the fuse is open:
Troubleshooting
Check PA, PB, CH coils for short to ground, if short is found:
Corrective Action
Replace the defective coil.
Replace the fuse.
Component
Check F3B, if the fuse is open:
Troubleshooting
Check CF, ES, EF, HR coils for short to ground, if short is found, coil is de-
fective.
Corrective Action
Replace the defective coil.
Replace the fuse.
Component
Check Voltage at the output of F3A and F3B:
Troubleshooting
If voltage is present at both F3A and F3B, it indicates a defective micropro-
cessor.
Corrective Action
Refer to Controller Service
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