Noticed this morning, that although the boiler is functioning as it should, the pump does not seem to stop. I checked this by removing the wiring to the pump, however when reconnected regadless of the ignition state of the boiler it seems to be running (so switch off boiler for now since would this not burn out the pump motor?) Any help welcomed.

John, September 2007

could be a motorised valve microswitch jammed! if you have a S plan system the pump and the boiler are wired into a switched live. if the micro switch is jammed then the pump AND the boiler will be constantly on, you may not realise the boiler is on cos it will only run for about 30 seconds before the boiler stat cuts out and stops the boiler from running so you may not realise it is running!

hope this helps!

KAW!, October 2007

Assuming the pump is wired to the pump supply from the boiler, it must be a faulty pump overrun thermostat.

Red Baron, September 2007