Good morning,

Friends of mine have a Vailant Turbo Max 828E, they say heating apparently works fine however when they turn the hot water tap on they get luke warm water.

I have had a quick look, the boiler fires up when DHW is demanded but shuts down after a few seconds; it then re-ignites after a few seconds with the hot tap left running then shuts shuts down again - it keeps cycling like this. Would appreciate some guidance to what it might be and where the component is located on the boiler.

Thanks in anticipation.
kind rgds
Mick

Mick, January 2009

Check if temperature shoots up after hot tap turned on
and boiler turns off. This is caused by a blocked or restricted by pass valve. Where is it? ON a horizontal pipe running across the rear about half way up. Cleanable!

mike h, February 2010

where is the diverter valve? On the lower r/h side. brass valve which joins onto the hot water heat exchanger. Has a black top with wires attached, do not play with it get a new one. 80 to 100

mike h, February 2010

see if accuator is still connected to valve remembering it has to pull and push.

mike h, February 2010

Hi I have seen similar query on this forum and i have the same problem and read its the diverter valve is there a way of testing this ? and can it be confirmed that it definately is the solution .

col del sol, January 2009