E: 18. External Communication Error (Indoor Unit) - Fujitsu AUXG36KRLB Service Manual

2-4. E: 18. External communication error (Indoor unit)

Wired remote
Indicator
controller
Detective actuator Indoor unit
Forecast of cause
Check point 1. Check the connection
• Check any loose or removed connection between the main PCB to the external input and out-
put PCB.
-> If there is an abnormal condition, correct it by refer to the installation manual or the "DESIGN
& TECHNICAL MANUAL".
• Check the connection condition on the external input and output PCB and the main PCB (If
there is loose connector, open cable or mis-wiring.)
Check point 2. Replace the external input and output PCB
If check point 1 do not improve the symptom, change external input and output PCB
Check point 3. Replace main PCB
If check point 2 do not improve the symptom, change main PCB
2-4. E: 18. External communication error (Indoor unit)
Error code
External
communication
error
↓
↓
↓
End
After receiving a signal from the external input and
output PCB, the same signal has not been received for
15 seconds.
Connection failure
External input and output PCB failure
- (03-9) -
E: 18
Main PCB
2. Troubleshooting with error code