Your boiler's internal components are having trouble communicating with the main control board, preventing the system from starting up.

DHW sensor fault: DHW sensor (8000 - 20000 ohms at room temperature), Wiring and connections to sensor.

What causes this fault?

This fault occurs when the boiler's main control board loses its digital connection with internal components like the display or the heat engine sensors. It is usually caused by a loose connection in the internal wiring or a physical failure of the electronic circuit board itself, preventing the boiler from sending start-up commands. In some cases, moisture ingress or a power surge may have damaged the sensitive communication pins on the board.