While you wait for answers, we may have found some information which could help you.
Click here for Boiler Combi Vaillant
We have no hot water?
Vaillant turboMAX 824E?
water dripping out of overflow pipe from boiler when CH on?
How can I fix my vailant boiler which is reading f.22 water shortage?
Vaillant Turbomax 824 overheats very quickly in heating mode?
Diverter Valve Replacement?