Heat Controller B-MMC09FA-1 Service Manual page 72

Troubleshooting Guide
Error
code
Communication
05 / 53
➔ Outdoor)
(Indoor
❑ Check Point
1. Check the input power AC 230V.(Outdoor, Indoor)
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.
72 Multi type Air Conditioner
Title
• Communication poorly
Cause of error
• Power input AC 230V.(Outdoor, Indoor)
• The connector for transmission is disconnected.
• The connecting wires are misconnected.
• The GND 1,2 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 & Normal condition