Your boiler's control panel has likely detected moisture or dampness inside the screen or buttons, preventing it from working correctly.

Service mode indicator flashing on digital display during combustion adjustment (minimum fan speed)

What causes this fault?

This fault occurs when the boiler's control panel detects moisture or condensation within the electrical circuits of the display screen. The most common reason is water ingress from a leak elsewhere in the boiler or high humidity causing dampness behind the buttons. When this happens, the interface becomes unresponsive to prevent a short circuit, resulting in a system shutdown.