Multi F Four-Way Ceiling Cassette Service Manual

Part 5. Trouble Shooting
- 97 -
Copyright ©2014 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
< MAIN PCB >
53
Title
Communication
(Indoor → Outdoor)
• Communication poorly
• Power input AC 230V. (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.
Display
code
Title Cause of error Check point & Normal condition
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 connected.
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
CH53 : Check the CN_COM and CN_POWER is correctly connected.
• 36k
1. In Case of CH53, Check the Connection
→ L,N at the terminal block
• 54k
1. In Case of CH05, Check the Connection
→ CN_POWER, CN_COMM at the Main PCB
2.
In Case of CH53, Check the Connection
→ CN_COMM at the Main PCB → L, N at the terminal block
N
CN-Power
CN-COMM
L1
L2
< TERMINAL BLOCK >
WARNING
Before checking PCB or each outdoor electric parts, wait for 3 minutes after the power is off. When measuring at standby state
of power supply, after checking the measurement mode of the meter, be careful of the short-circuits with other parts.
L1 L2
L1
L2