LG ARNU Series, Service Manual

Page: 129 / 226

Service Manual 129
Troubleshooting Guide
Communication
error between the
Outdoor and
Indoor Unit
Error
Code
Error Contents Meaning Main Causes
Error display
position
05
In case the Indoor Unit
does not receive any signal
from the Outdoor Unit .
Concerned
Remote controller
Panel Display
1. Defective "Auto-Addressing"
2. Defective communication connec-
tions between Indoor and Outdoor
Unit
3. Communication cable is open or
short
4. Defective Indoor Unit communica-
tion circuit
5. Defective outdoor unit communica-
tion circuit
6. Insufficient distance between the
power line and the communication
cable
7. Outdoor main power Line Fuse
damage.
■
Defect inspection method :
[In case all Indoor Units display 'ch05' error code ]
1) Check whether the "Auto-Addressing" was in operation or not.
2) Check whether the Outdoor Unit power is off .
If the Outdoor Unit power is Off then check the cause and put the power On. (Cause : Comp electric leakage
or damage, ELB (breaker) defect, electric short between the power line etc )
3) Check whether the outdoor control box communication wire is connected properly at the terminal
4) Check whether the communication wire is open or short , in such a case remove the defect cause.(Wire open
confirmation : After power Off, short the communication wire with each other and measure the resistance of
the communication wire by a tester › In case the resistance is above 5
Ω
, then the wire is open (Wire short
confirmation : After power Off, separate the communication wire and measure the resistance of the communi-
cation wire by a tester › In case the resistance is below 5
Ω
, then the the wire is short )
5) In case the causes mentioned in clause 1)~3) does not exists, then all communication wire of the Indoor Unit
must be separated and the all Indoor Unit communication wire by connecting to the Outdoor Unit one by one .
(Defective Indoor Unit PCB connection can cause the communication error ) › Replace the concerned Indoor
Unit PCB.