E7 (15 flashes) — Communication fault between indoor and outdoor units (All-in-one board)

What does E7 (15 flashes) mean?

On all-in-one board systems, this error (indicated by 15 flashes on the outdoor unit's LED2) signifies a communication breakdown between the indoor and outdoor units. This usually points to wiring or PCB problems.

• Communication wiring disconnected
• Indoor PCB is broken
• Outdoor PCB is broken

Click steps to track your progress.

1. 1

   Turn off the power switch before inspecting connections.

2. 2

   Ensure the linking cable between the indoor and outdoor units is properly connected, insulated, and polarity is correct.

3. 3

   Reconnect or replace the linking cable if necessary.

4. 4

   Restart the air conditioner to see if the error is cleared.