Combi been in about 3 years. Works fine on heating side. In the last couple of weeks HW side only provides only warm water. Not hot as before. Setting not changed since installation.

Anybody any ideas... Thanks

Mike, March 2008

thanks for that, didnt workthough.

system doesnt start under dhw only, works perfectly on ch side

Mike, April 2008

could be divertor valve sticking slightly in ch, to check.
allow ch sys to cool totally then set hot tap away and feel the ch pipes under the boiler generally 22mm rather than 15mm. if they get mad hot thats your problem.
another possibility is scaled up exchanger giving poor heat transfer to the dhw

iain, March 2008