Service Diagnosis
55
L4
Description
Heat sink overheat
Possible Root
cause
1. Fin temperature rise due to short circuit.
2. Fin temperature rise due to defective outdoor unit fan.
3. Fin thermistor defective.
4. Connector in poor contact.
5. Outdoor unit PCB defective.
6.
Silicon grease is not applied properly on the radiation fin after replacing outdoor unit PCB.
Troubleshooting
*Remark:
Refer to Appendix A for outdoor fan system check.(Page 72, item 6.7)
Refer to Appendix A for installation condition check. (Page 71, item 6.6)
Yes
Error displayed
again?
s
e
Y
s
e
Y
No
Turn off the power and turn it on
again to start the system.
Has the PCB been
replaced?
Above
A
°C?
Check the radiation fin
temperature.
Check the
outdoor fan.
Malfunction
No
Functioning
Radiation fin dirty?
Yes
Check if silicon grease is
applied properly on the
radiation fin. If not, apply
the silicon grease.
Replace the outdoor fan
motor.
Correct the connectors and
fan motor leads.
Replace the outdoor unit
PCB.
Replace the outdoor unit
PCB.
Check the installation
condition.
Clean up the radiation fin.
No
No
Models
A °C (°F)
Class 09/12
93 (199.4)
class 18/24
85 (185)
