LG ARUN Series Service Manual page 108

Troubleshooting Guide
Error
Error Type
No.
Communication error
52*
between
Master 521
(Inverter PCB ➔ Main PCB)
Slave 522
I Error diagnosis and countermeasure flow chart
Is communication
LED (Yellow) of inverter
compressor
PCB on?
Yes
Is communication cable
connected correctly?
Yes
Is MAIN PCB normal?
Yes
Replace inverter compressor PCB
* The method of checking MAIN PCB and inverter compressor PCB (If normal, communication LED blinks)
Communication connector & LED in MAIN PCB
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Error Point
Main controller of Master
unit of Master unit can't
receive signal from
inverter controller
No
Is noise filter or fuse
normal?
Yes
Replace inverter compressor PCB
No
Re-connect communication cable
No
Replace MAIN PCB
Communication connector & LED in inverter compressor PCB
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Main Reasons
1. Power cable or communication cable is not
connected
2. Defect of outdoor Main fuse/Noise Filter
3. Defect of outdoor Main / inverter PCB
No
Replace noise filter or fuse
LGE Internal Use Only