worcester 240 diverter valve problem

[KatRyder]

Firstly hello all!!

We've had the diaphragm replaced on our boiler as the old one was perished, leading to no hot water.

However now the new one is in it's not moving enough to make contact with the micro switch to fire the gas. Yet there is nothing obvious causing obstruction and moved freely with pliers pulling gently in and out.

Any ideas?

 

[oilhead]

You say you've 'HAD it replaced', so presumably you've paid someone to do it. If so, the answer is get them back.
It is probable that the spring is either jammed or obstructed, so that when the water pressure is relieved, it is not pushed up enough, but appears to be free when you pull. A good service kit will have a completely assembled unit, but many service personnel just assemble an old spring and plate to a new diaphragm as it is cheaper.