Troubleshooting Guide
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Only for training and service purposes
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03 Bad communication between control panel
and indoor uni
• Incorrect
connection
between
sensor and
PCB
• PCB fault
• Sensor fault
• Wire connection between control panel
and indoor unit PCB should be tight
• Output voltage of PCB should be 12Vdc
Code
No.
Description Cause Normal Condition
■ Error diagnosis and countermeasure flow chart
After replacing the control panel or indoor unit PCB, it is very important to perform parameter setting by
‘entering Installer Setting Mode’ at the control panel.  
If not, system will NOT be operated correctly. It is STRONGLY recommended to keep above instruction.
Check the Voltage.
Indoor Unit
V
12Vdc
12V
(RD)
S
(YL)
GND
(BK)