While you wait for answers, we may have found some information which could help you.
Success
Message
boiler starts then soon stops?
HW issues w. Vaillant boiler?
Re Pressurise system?
water dripping out of overflow pipe from boiler when CH on?
vaillant boiler trips house electrics when hot tap on?
Diverter Valve Replacement?
Vaillant Turbomax 824 overheats very quickly in heating mode?
Vaillant turboMAX 824E?
Boiler over pressure on the hot-water side?
We have no hot water?
SERVO VALVE ON VAILLANT BOILER?
Cannot turn radiators off,?