Make sense but In my setup I have a second, EOM factory installed, leisure battery that I believe is connected to the webasto and the alternator for re-charge. Do you think is possible to increase the 120m via VCDS?Yes, 120 minutes indeed is the maximum. A reason for the limitation might be relatively high "battery" consumption. The factory setup draws approx. 12 Amps at full power - heater itself, coolant pumps and the blower. Thus running the heater overnight most likely flattens the battery (12A x 8h = 96 Ah, which is full battery capacity).
Actually the temperature can be controlled - the temperature is set by the normal Climatic heater/air conditioner dial. Also air flow direction is controlled by normal dials. Only the blower speed can't be adjusted - it runs always at speed 2. When the set temperature is reached the Webasto ramps the burner power down and can be turn it completely off from time to time.
Good to know, thanks
I think the overhead control panel in California runs the auxiliary air heater only - thus most likely those functions are not available for water heater. Also the overhead control panel is wired differently.
Thanks for sharing.