I have recently moved boiler to loft and ever since the hot water, wont get hot only warm then cold then warm again and so on, the CH works fine ,, i have checked the continuity of the NTC's wiring (all three of them )and all seems fine there any ideas please or should i try replacing NTC's first (there are 3 altogether 2 on return and 1 on flow) the boiler worked fine before we moved it. i dont like cold showers this time of the year ,, PLEASE HELP.

lee, December 2008

hi there
I am having problems with the same model ( not your problem though ( bar pressure not holding) so was looking through this interesting site for Vaillant Boilers.
I certainly think you have a diverter problem. We have had 3 replaced in 6 years ( hard water area doesn't help- I suspect some sediment has blocked needle size holes -they are so tiny it doesn't take much to block) also the early models they constructed the component in the wrong materials -engineer told me. hope that helps -Back to my problem. JAB

JAB, January 2009

I think it could do with needing a new diverter valve from reading others problems on sites. I have same probelm and just ordered a new one

Tony Lee, December 2008