How do i replace mt10 timer on worcester-bosh green star cdi boiler.Timer itself works but will not fire up boiler when set to

ian, January 2010

do you mean it hold the correct time but does not fire the boiler? does it work when set to constant? if so then it may well be a faulty timer.

this is a simple job, and you do not need to touch anything to do with the gas, but unless qualiifed to do so you should not do this by yourself. you need to remove the combsustion cover to do the job, and if you don't put it back on correctly the you could end up with fumes leaking into the room. a performance test shold also be carried out after removing the combustion cover.

Ian, January 2010

I am an unqualified mupppet when it comes to boilers but if the Timer works as you say it does there is little point putting in another working timer.

Your timer is either telling the boiler to start up or it isn't - the boiler may be failing to respond to the request from the timer - or there is no request.

Diagnosis is usually cheaper and quicker than guessing.

Good luck...

Peccavi, January 2010