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18.5.21 Indoor-Control Panel Communication Abnormality (H76)
Malfunction Decision Conditions:
During standby and operation of cooling and heating, indoor-control panel error occur.
Malfunction Caused:
1 Faulty connector connection.
2 Faulty control panel.
3 Faulty indoor unit PCB (main).
Troubleshooting:
For safety reason and to prevent component breakdown,
always switch off the power before remove and connect the component.
Check the CN4 connector connection:
- Turn OFF the power
- Check the connector connection
Check the Vdc from the indoor unit PCB (main):
- Disconnect remote control from the indoor unit PCB
terminal CN4
- Turn ON the power.
- Measure the Vdc as shown in Figure 1.
- Is the Vdc measurement 16Vdc?
Is the CN4 connector
connection normal?
- Defect in indoor unit PCB
(main).
- Replace the indoor unit PCB
(main).
Check the control panel
cable connection.
Is the control panel cable
connection normal?
- Defect in cable connection.
- Replace control panel cable.
- Connector poor contact.
- Correct the connection.
- Defect in remote control
(control panel).
- Replace the remote
control (control panel).
Yes
Yes
Yes
No
No
No
Caution
Figure 1
16Vdc