H11 — No communication between indoor and outdoor unit

What does H11 mean?

There is a failure in communication between the indoor and outdoor units. The control board may be defective, or there's a wiring issue.

• Communication cable is broken or disconnected.
• Control board in either unit is defective.
• Interference on the communication line.

Click steps to track your progress.

1. 1

   Check the communication cable between the indoor and outdoor units.

2. 2

   Ensure all connections are secure.

3. 3

   Inspect the control boards for any visible damage.

4. 4

   Turn off the unit, unplug it, wait 30 seconds, and plug it back in to reset.