Your boiler has lost its display and controls, which usually means the main internal circuit board has failed while the pump is stuck in a backup safety mode.

No display, pump running

What causes this fault?

This issue occurs when the boiler's central brain, the printed circuit board, suffers a critical electronics failure or loses power entirely. It is usually caused by an internal electrical short or a worn-out component on the board that prevents it from communicating with the display. Because the control board can no longer manage the system, the pump stays running as a built-in safety measure to prevent the unit from overheating.