CH05 - Communication error between indoor and outdoor units

What does CH05 mean?

This code signifies a communication problem between the indoor and outdoor units, appearing about 5 minutes after the system powers up. The communication signal is a fluctuating DC voltage.

• Incorrectly installed interconnecting wiring
• Loose or damaged wiring connections
• Interfering devices connected to the communication line

Click steps to track your progress.

1. 1

   Ensure both 'Comms' and 'Neutral' connections on the interconnecting cable are un-switched.

2. 2

   Verify that all connections at both the indoor and outdoor units are correct and securely fastened.

3. 3

   Temporarily remove any other devices connected to the interconnecting cable to see if the fault clears.

4. 4

   Check the interconnecting cables for any short or open circuits, as well as connections between the terminal rail and the PCB on both units.