LG LMNH122LRA0 Service Manual page 117

4) Troubleshooting CH05, CH53
Display
Title
code
04
Communication
/
(Indoor
53
Cause of error
• Communication poorly
Outdoor)
Check point & Normal condition
• Power input AC 220V. (Outdoor, Indoor)
• The connector for transmission is disconnected.
• The connecting wires are misconnected.
• The GND1,2 is not connected at main GND.
• The communication line is shorted at GND.
• Transmission circuit of outdoor PCB is abnormal.
• Transmission circuit of indoor PCB is abnormal.
Check Point
1. Check the input power AC380~450V. (Outdoor, Indoor unit)
2. Check the communication wires are correctly connected.
Adjust the connection of wire
Confirm the wire of "Live", "Neutral"
3. Check the resistance between communication line and GND.
(Normal : Over 2MΩ)
4. Check the connector for communication is correctly
connected.
5. Check the connection of GND1, GND2, and main GND.
6. If one indoor unit is operated normally, outdoor PCB is no
problem.
Check the another indoor unit.
* CH05 is displayed at indoor unit, CH53 is displayed at outdoor
unit.
Troubleshooting Guide
Service Manual 117