Taming a Webasto Dual Top Heater

Taming a Webasto Dual Top Heater

Taming a Webasto Dual Top Heater

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Forego the certainty of hot water for morning ablutions unless the Webasto is manually set to Hot Water mode two hours beforehand

The Webasto Dual Top Heater is a complex piece of equipment from which it can be difficult to get the required combination of heating and hot water without an understanding of how it operates. Often this is most apparent when hot water is required for the morning ablutions. When the Webasto is set to Heating Cabin + Hot Water it will prioritise heating and only once the cabin has reached the set temperature will it produce hot water. Also while producing hot water the Webasto will undertake a purge cycle every 45-50 mins and at least 75 minutes need to be allowed for the water to reach 70°C. Armed with this understanding and a little cunning the beast can be tamed.

Manual Use

Either allow sufficient time for the cabin to warm up and then for the hot water to be produced or manually select hot water mode.

Programmable Timer Use

By far the most convenient way to obtain hot water is to use the Programmable Timer. Sadly there is no Hot Water only mode so this is where a little cunning is required because to get hot water the timer has to be used in Heating Cabin + Hot Water mode. Now the timer has to be programmed in one hourly intervals and as at least 75 minutes are needed to produce a boiler full of hot water two intervals must be allowed for hot water production. In this two hour period the actual cabin temperature must be higher than the set temperature otherwise the Webasto will revert to heating. For each hourly interval the timer can be set to either: ‘Off’, a low cabin temperature or a high cabin temperature. The timer has two programs and the two cabin temperatures can be set separately for each of these programs.

In the summer, use one of the programs and set one of the cabin temperatures to a level which will be below the lowest expected cabin temperature. Now set each hourly interval in which hot water is required plus the two hourly intervals before that in which hot water is required to this set cabin temperature. All other hourly intervals should be set to ‘Off’. If the cabin temperature has been set low enough only hot water will be produced.

In the winter, use the alternative program and set one temperature to the required day time temperature and the other temperature to a lower or night time temperature. Now set each hourly interval as required but remember hot water will only be produced if the cabin has reached the set temperature. So sufficient time has to be allowed for the cabin to reach the required temperature at least two full hours before the hour in which hot water is required. In practice if the Webasto has been set to ‘Off’ overnight the best sequence to follow for hot water in the morning is to set timer to the lower temperature three hours before hot water is required and the higher temperature one hour before hot water is required. If the Webasto has been heating the cabin overnight then because it is being used in Heating Cabin + Hot Water mode the water should be hot, provided the Webasto has been able to achieve the set temperature for at least two hours before hot water is required.


Perseverance in reading this far and investing the time in setting up the Webasto using the techniques above will be rewarded with a lie in, a warm van and hot water for morning ablutions.



2 thoughts on “Taming a Webasto Dual Top Heater

  1. Colinablitt

    When the timer is in use is the frost protection automatically on or in winter does one have to set a low cabin temperature for the times that the van is not occupied?

  2. John Laidler

    I’ve tried this but with ours, even when it shouldn’t be heating the interior of the vehicle it blows out a bit of hot air when it is heating the water. This isn’t very welcome if it is very hot outside. 🙂
    Ideally, as suggested, it should be possible to time hot water only heating but this isn’t available for some perverse reason.

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