LG MULTI V M ARNU07GTU 4 Series Svc Manual page 77

Error
Error Type
No.
Communication error
(Indoor unit ' Compressor
531
Module Main PCB)
n Error diagnosis and countermeasure flow chart
Is power supplied
to indoor PCB?
Yes
Is communication cable
connected correctly?
Yes
Are quantity of indoor
Units installed same as
The data of LGMV?
Yes
Check communication cable
and installation
In case of CH53, almost happened with CH05, the indoor units not operated actually are normal so check with same
method of CH05. and additionally check as shown as below and above flow chart
• Although the quantity of indoor units installed is same as LGMV data there may be a few indoor units with which the
number of communication is not increased with LGMV
• Although the quantity of indoor units installed is not same as LGMV data, and if communication of the indoor unit
displayed at LGMV is done well then the indoor unit suspected to have some problem (and is not appear at LGMV)
may have following problems
¿ wrong connection of communication cable or power cable
¡ fault of power / PCB / communication cable
¬ duplication of indoor unit number
• If communication is not doing well wholly then the Auto Addressing is not done
• The case that CH53 appear at indoor unit also Auto Addressing is not done so indoor unit address may be duplicated
* After replacement of indoor unit PCB, Auto Addressing should be done, if central controller is installed then the
central control address also should be input.
In case that only communication PCB is replaced above process is not needed
Error Point
In case Compressor
Module Main PCB can't
receive signal from indoor
unit
No
Supply power
1. Check communication cable between External and indoor PCB
→ Re-connect communication cable
2. Check communication cable between Cycle and External PCB
→ Re-connect communication cable
No
3. Check communication cable between Cycle and Communication PCB
→ Re-connect communication cable
4. Check communication cable soldering correctly
→ Replace communication cable
No
1. Is indoor unit quantity correct after auto addressing
→ Check Communication PCB
2. Check communication PCB LED blinking
→ Replace communication PCB
3. Auto addressing after replace Communication PCB
→ Check outdoor Main PCB
1. Communication cables are not connected between
External PCB and indoor PCB
2. Communication cables are not connected between
Main PCB and External PCB
3. Communication cables are not connected between
Main PCB and Communication PCB
4. Communication cables are short/open
5. Indoor PCB power off
6. Defect of outdoor Cycle/Communication/indoor PCB
7. Communication wire connection fault
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