LG ACHH Series Manual page 80

Error code check
Error number Errors
Communication error :
57
CYCLE Main PCB ÷
(571)
Inverter PCB
n Failure diagnosis method
Are there any
communication wire
connections normal?
Yes
Is inverter PCB
assembly
normal?
Yes
Is there any error
when power reset?
No
Recheck power and
installation condition
Fan board
Communication
LED
Communication
LED
※ In case where a wire connector terminal has a contact defect and is inserted incompletely, be sure to turn off
the outdoor unit power circuit breaker and then reset the power when confirming.
Meaning
1. Bad Connection Between Inv and Main
Failing to receive
2. Communication Wire Noise Effect
inverter signal at main
3. CYCLE Main PCB Damage
PCB of Outdoor Unit
4. Inv PCB Damage
No
1. Check communication wiring conditions
2. Check connector conditions
→ Rewire them if abnormality found.
No
1. Replace Inverter PCB
Yes
1. Replace CYCLE Main PCB
Inverter PCB 1
- 80 -
Main cause of occurrence
Inverter PCB 2
Communication
LED
Main PCB
Communication LED