I have a Vaillant combi approx 7years old and to be honest it has always been a bit iffy from day 1...water going cold while the bath has half filled etc.
The problem is that when the heating is turned off and the water only is selected, the heating comes on regardless. I have turned down the roomstat to nil and it appears to be functioning normal. The only way in any format to get hot water only is to have the heating on. I do not have a timer clock fitted to my system so that would eliminate that poosible cause.
So, what do you think guys?
I am pretty ept in most fixits so, is this a job I could do myself. On a diy scale of 1-10 I am about 8.