Cannot communicate with indoor unit — System cannot connect to the furnace or fan coil

What does CANNOT COMMUNICATE WITH INDOOR UNIT mean?

The Evolution Control is unable to establish communication with the main indoor heating or cooling equipment. This message appears during the initial power-up sequence and must be resolved for the system to function.

• Loose or damaged wiring on the ABCD bus
• Faulty indoor unit
• Faulty Evolution Control unit

Click steps to track your progress.

1. 1

   Check that all wiring connections to the indoor unit and the Evolution Control are secure.

2. 2

   Ensure the ABCD bus wiring is not damaged or kinked.

3. 3

   Try resetting the system by turning off power at the circuit breaker for 30 seconds, then turning it back on.