SiUS041501E Troubleshooting
Service Diagnosis 88
4.21 Radiation Fin Temperature Rise
Error Code L4
Method of Error
Detection
A radiation fin temperature rise is detected by checking the radiation fin thermistor with the
compressor on.
Error Decision
Conditions
If the radiation fin temperature with the compressor on is above A.
The error is cleared when the radiation fin temperature drops below B.
If the error repeats, the system is shut down.
Reset condition: Continuous run for about 60 minutes without any other error
Supposed
Causes
Defective outdoor fan motor
Short circuit
Defective radiation fin thermistor
Disconnection of connector
Defective outdoor unit PCB
Silicon grease is not applied properly on the radiation fin after replacing the outdoor unit PCB.
Troubleshooting
Check No.17
Refer to P.98
Check No.19
Refer to P.99
Note: Refer to Silicon Grease on Power Transistor / Diode Bridge on page 108 for detail.
AB
°C °F °C °F
09/12 class, RKN18NMVJU 99 210.2 70 158
RXN18NMVJU, RK(X)18NMVJU, 24 class 100 212 57 134.6
Caution
Turn off the power and turn it on
again to start the system.
Be sure to turn off the power switch before connecting or disconnecting
connectors, or parts may be damaged.
(R21672)
NO
NG
OK
NO
YES
Check the radiation fin
temperature.
NO
YES
YES
Above A?
Check No. 19
Check the outdoor fan.
Error displayed again?
Has the PCB been
replaced?
Check if silicon grease is
applied properly on the
radiation fin. If not, apply
the silicon grease.
Replace the outdoor unit
PCB (main PCB).
Replace the outdoor fan
motor.
Correct the connectors and
fan motor leads.
Replace the outdoor unit
PCB (main PCB).
YES
NO
Radiation fin dirty?
Clean up the radiation fin.
Check the installation
condition.
Go to Check No. 17.
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