Combi Boiler problem

[Astonishingmonkeyman]

I have an Icon 23t combi boiler situated in my upstairs bathroom.
All has been fine with it until recently. Now, if I turn on the hot tap in the bathroom the boiler fires and the water gets hot as it should. If I turn on any of the downstairs taps or the try to use the downstairs shower, the boile doesn't fire at all. CH works fine.
Any ideas?

 

[chrishutt]

Sounds like a diaphragm problem. Does the hot tap that works give a stronger flow than those that don't? If diaphragm is developing a split, it will only work when flow rate high (until it stops working altogether).

 

[trev123]

the diaphgram in the water section has developed a split not allowing the push rod to make its connection

 

[Astonishingmonkeyman]

Thanks guys. I will give it a try.