Indoor unit communication fault

What does INDOOR_COMM_FAULT mean?

There is a communication error between the main control unit and the indoor equipment. This prevents proper system operation.

• Wiring issue on the ABCD bus
• Damaged communication cable
• Indoor unit control board failure
• Interference on the communication line

Click steps to track your progress.

1. 1

   Recheck all wiring connections to the ABCD terminals on the indoor unit and control.

2. 2

   Ensure all wire colors match at each terminal.

3. 3

   Try disconnecting and reconnecting the communication wires.

4. 4

   Contact an HVAC technician if the communication issue persists.