vaillant turbomax no hoy water

[shuffmuff]

hi, i have a problem with my vaillant turbomax which is heating the central heating perfect, but not the hot water through the taps.
with the setting on hot water only the light on the boiler for hot water is hardly lighting up and is very weak looking and the arm on the diverter valve will not close fully down.
but with both hot water and radiators on, the light on the boiler is a bit stronger and the arm will work but i still get no hot water for any good amount of time.
also the burner keeps cutting out with the settings on both and the hot water taps are open, it fires up but shuts off again straight away and leeps trying to relight with no success.
i hope this is plenty info, thanks.

 

[twgas]

Which turbo max is it?

 

[shuffmuff]

nor sure, has the old black face, been installed since 2001

 

[twgas]

Do you mean black fasciaa behind the bottom door, and green knobs?

 

[shuffmuff]

yes thats right

 

[Agile]

Sounds like the diverter valve has failed.

Not such a nice job for a professional and so not very good for a DIYer either!

Tony