Self-diagnosis function
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Only for training and service purposes LGE Internal Use Only
1. Auto addressing is not done
2. transmission cable is not connected
3. Short circuit of transmission cable
4. Indoor unit transmission circuit fault
05 5. Outdoor unit transmission circuit fault
6. Not enough distance between power and trans-
mission cable?
Error
No. Error Type Error Point Main Reasons
No signal transmission
between indoor & outdoor
units.
Indoor & Outdoor unit
transmission error
Does all the IDUs show
same error code CH05?
Is outdoor PCB LED
blinking?
Yes
Yes
No
Is main circuit breaker off?
No
Check the main power
supply at the ODU
terminal block?
Improper connection of power supply cable
Main power supply problem
Yes
No
Yes
No
Outdoor PCB fault
Replace after checking
Re connect transmission cable
No
Yes
Indoor PCB fault
Replace after checking
* (Note1) Transmission from IDU is normal if voltage
fluctuation(-9V ~ +9V) exists when checking DC voltage
of communication terminal between IDU and ODU
Is total number of indoor
units connected displayed
after auto addressing?
No
END
* If the DC voltage between transmission terminal A, B
of indoor unit is fluctuate within (-9V~+9V) then
transmission from outdoor unit is normal
Check the insulation of inverter
/ constant compressor and replace
if required
Check the capacity of main circuit
breaker and replace if required
If all ok,
Turn on main circuit breaker
Replace outdoor PCB after
checking
Replace TRANS after checking
Replace the PCB of indoor unit
displayed error
Re-connect after check the
transmission cable of indoor
unit displayed error**
Check if the
transmission cable is
properly connected
to indoor / outdoor
terminal block?*
■Error diagnosis and countermeasure flow chart