Ariston Eurocombi Heat Exchanger?

Your problem is probably the 3 way divertor valve.

If the primary heat exvchanger is blocked yiou will not get hot water as the primary heat exchanger provides the hot water to the secondary DHW heat exchanger - via the 3 way divertor valve.

Go here

http://www.bes.co.uk/products/114.asp

and search for P/N 17091

This is the correct valve and a third of the price elsewhere

£23.25 plus vat - got mine yesterday for £28 and picked it up in Birmingham.

This valve does sludge up and jam.

It is a DIY fix if you are reasonable competant with spanners.

No gas to discinnect / mess with

Also for other spares try http://www.mjtcontrols.co.uk

main heatechanger heat £95 plus vat, but this part is easily removed and cleaned. if it does not leak you can clean it out.

hth

EliTom
April 2008