LG ARUV Series Service Manual page 250

Troubleshooting Guide
Error
Error Type
No.
Indoor & Outdoor unit
05
transmission error
Error diagnosis and countermeasure flow chart
Does all indoor show
this error code CH05?
Yes
Is outdoor PCB LED
flickering?
Yes
Check if the
transmission cable is
properly connected
to indoor / outdoor
terminal block?*
Yes
* If the DC voltage between transmission terminal A, B
of outdoor unit is fluctuate within (-9V~+9V) then
transmission from indoor unit is normal
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Error Point
No signal transmission
between indoor & outdoor
units.
No
Is total number of indoor
units connected displayed
after auto addressing?
END
Is not the power
No
supplied at main terminal
block of outdoor unit ?
Yes
Is main circuit breaker off?
Yes
Bad connection of power supply cable
Main power supply problem
No
Re connect transmission cable
Outdoor PCB fault
Replace after checking
Indoor PCB fault
Replace after checking
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Main Reasons
1. Auto addressing is not done
2. transmission cable is not connected
3. Short circuit of transmission cable
4. Indoor unit transmission circuit fault
5. Outdoor unit transmission circuit fault
6. Not enough distance between power and trans-
mission cable?
7. Is the fuse for main PCB power of outdoor unit
burnt out?
Replace the PCB of indoor unit
No displayed error
Re-connect after check the
transmission cable of indoor
unit displayed error**
Replace outdoor PCB after
No
checking
Replace TRANS after checking
Replace main PCB fuse after
checking
Check the insulation of inverter
No
/ constant compressor and then
replace it
Replace after capacity of
main circuit breaker?
If nothing goes wrong,
Turn on main circuit breaker
* If the DC voltage between transmission terminal A, B
of indoor unit is fluctuate within (-9V~+9V) then
transmission from outdoor unit is normal
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