LG Multi-Inverter Service Manual page 106

¢º ¢º A7UW428FA3/A8UW488FA3/A9UW548FA3
Display
Title
code
05
Title
/
Communication
(Indoor ¡ Outdoor)
53
Check Point
1. Check the input power AC230V. (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 con-
nected.
5. 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.
6. If all indoor unit is displayed CH05 but outdoor PCB not
display
1) In Case of CH05, Check the Connection
¡ CN-POWER, CN-COMM at the Main PCB
¡ CN-MAIN at the Noise Filter
2) In Case of CH53, Check the Connection
¡ CN-COMM at the Main PCB
¡ CN-MAIN-COMM, CN-AC-220V at the Inverter PCB
¡ CN- INVERTER at the Noise Filter
Copyright ©2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
Cause of error
• Communication poorly
CN-MAIN CN-MAIN CN-MAIN
- 105 -
Check point & Normal condition
• Power input AC 220V. (Outdoor, Indoor)
• The connector for transmission is disconnected.
• The connecting wires are misconnected.
• The communication line is shorted at GND.
• Transmission circuit of outdoor PCB is abnormal.
• Transmission circuit of indoor PCB is abnormal.
CN-Power CN-Power CN-Power
< MAIN PCB >
< Noise Filter >
< INVERTER PCB >
4. Trouble Shooting
CN-COMM CN-COMM CN-COMM
CN-INVERTER CN-INVERTER CN-INVERTER
CN- CN- CN-
AC-220V AC-220V AC-220V
CN- CN- CN-
MAIN-COMM MAIN-COMM MAIN-COMM
LGE Internal Use Only