Plumbing/CH Query - Expansion Vessel

[ed_pete]

So this morning the pressure had dropped in the heating system sufficiently for the boiler to turn off. Not altogether unusual every so often. Re-pressured to 1 bar when cold. Now warm it's over 3 bar. I'm wondering if the expansion vessel has had it (it's about 11 years old) and diaphragm has leaked, hence pressure drop and now it's unable to soak up the pressure caused by the expanding hot water.

Any amateurs like to venture and opinion ?

[malumbu]

All my experiences with combis were bad, they don't seem to last that long. That said I switched to a condensing boiler in a traditional system. Lifetime even shorter by most accounts. Sorry not very helpful.

[CD_Rom]

Weirdly we've had exactly the same issue with our combi this morning too. Had an engineer attend who suspected the expansion vessel- apparently there's an emergency release over 3 bar hence the pressure building and then dropping to 0. Sadly in the end with our it turned out not to be the expansion vessel but the heat exchanger - so it's looking like new boiler time (ours is fairly old too and we've suspected it was on the way out for a while). Fingers crossed you have better luck with yours Pete!