Boiler now 2 years old. Works fine generally, however it has now started to operate even when the settings say it shouldn't.
Example 1 - Central Heating timer set for on. Room stat set low so boiler should not operate, however, sometimes it does. Thermostat checked and working fine.
Example 2 - woke up at 3am with central heating on. Timer setting was outwith the 'on' time settings so boiler should not have been on. Turned room stat down as low as it would go and boiler remained on. Only turning the mainswitch to 'Reset' cleared the problem.

Any insight would be appreciated as to what what component needs replaced.

thanks

Alastair

Alastair, July 2007

Many thanks for taking the time to reply - I will give this a try

regards

Alastair, July 2007

Could be the hot water microswitch is sticking or shorting out making the boiler fire for hot water even when the taps are closed. This would activate the boiler even when the clock was off.
It is mounted on the end of the diverter valve and held in place with a circlip. Turn the power off and remove it and see if there is water on the switch or check it with a multimeter circuit tester.

T.h.s, July 2007