Diesel powered cooktops/water heating

we have a wallas diesel cook top, an espar diesel hydronic heater, an indel marine hot water heater and 2 heat exchangers to provide heat for the cabin of a custom Mitsubishi Fuso FG offroad camper.

The espar unit can preheat the engine, heat the hot water or heat the cabin with thermostatic control or timer control.

The engine can heat the hot water and / or the cabin either while parked or driving.

We cook all our meals on the wallas cooktop including morning coffee and speed is never an issue. The cook loves the temperature control provided by the knob as well as the ability to slide the pan from the high temperature burner to the low temperature burner for instant, infinite heat control.

If we are parked such that the wind can blow directly in the stove exhaust outlet, we sometimes experience a little difficulty starting the stove. But that's easy to take care of by moving slightly or installing a protected smoke head on the exhaust.

I believe the Dometic version of the wallas cooktop exhausts through the floor and that would also solve the problem.

The 6 gallon water heater holds enough hot water after driving to provide hot water for showers and washing for a few days.

If we are parked longer than that 10 or 15 minutes use of the espar easily replenishes the supply.

After a week of camping we run the engine for 30 - 60 minutes to recharge the batteries and that replenishes the hot water tank as well.

We definitely like the single fuel source as well.
I'm currently building an off-road motorhome body from the floor frame up. It is on a MAN 13.280 4x4 chassis. Since posting my first enquiry, I've decided to use a Webasto diesel cooktop & diesel water/room heater. Just to have one fuel source is a great advantage, also not to have any combustion gasses in the living space is another.


Tony LEE

International Grey Nomad
In the OKA I've installed a Webasto cooktop and a webasto thermotop. The thermotop heats coolant which can be used to preheat the engine, heat 20Litres of water in a calorifier and also heat the cabin via a fan-forced radiator.
The engine also heats the calorifier as well while driving.
Both units are fuelled from a 30Litre SS tank which is filled from either one of the fuel tanks via a filter and an electric fuel pump.

The cooktop does take about 4 minutes to get up to temperature but that is just a matter of turning it on during the last part of food preparation.

Heat starts to come out of the cabin heater within a couple of minutes of switchon - immediately if the engine has been running.

All is working very nicely so far and using the thermotop - which heats coolant - means I can easily extend the system to provide extra cab heating or water tank heating if necessary. Not needed in Oz, but may be if I follow through with the plan to ship it to S America.

I have two water mixing (tempering) valves. One set at the right temperature for washing up feeds the HW tap at the sink and the other, set at the right temperature for showering feeds the outside shower.

Heating water for the roadside coffee stops is done with a 1kW electric kettle fed from a 1500W square-wave inverter. This means we don't have to deploy the camper to get at the fixed inside cooktop and means we can heat the water a drink the coffee in less time than it would take to fire up the webasto. That is so convenient that we use the electric kettle for drinks even when we are set up for camping


Expedition Leader

Gotta have the Java!:coffeedrink:

If I can ask a really NEWB question...How does the water, the potable water specifically, get heated via the engine without coming in contact with antifreeze? *embarrassed...*

Tony LEE

International Grey Nomad
Gotta have the Java!:coffeedrink:

If I can ask a really NEWB question...How does the water, the potable water specifically, get heated via the engine without coming in contact with antifreeze? *embarrassed...*

A 20L SS insulated container full of water (potable), and pressurised by 12V water pump has a SS coil immersed in in. The coolant - heated either by the engine or by the Webasto - runs through the coil, thus heating the water.
The webasto system and the engine system are interconnected so uses the same antifreeze/antiboil mixture. Can be isolated from each other and operated separately if necessary. The basic Perkins motor really appreciates it when the mornings are cold enough for me to want the heater on before I get out of bed because it also gets nice and warm before having to start.

It is not unknown for a leak to result in contaminated water, but I guess taste, smell or appearance would show something is wrong. Actually that system on the OKA draws water from 2 tanks which may contain potable water or as is the case at the moment in the Simpson desert, from non-potable sources (artesian bore water) - whatever is available. Only used for dishwashing and showers so doesn't matter too much. Drinking water comes from two other tanks totalling 170 Litres with a separate pump so I can be fairly sure that water stays OK to drink

Potential temperature of the hot water can be up to 85C - hence the tempering valve(s) to mix it with cold water before distribution to the taps.

The webasto has a circulating pump that circulates the heated coolant through the coil in the HW tank (called a calorifier in Europe) and/or the engine (to preheat in very cold weather and/or the fan forced heater coil in the camper.

If the webasto is off and the engine running then the engine coolant pump sends the same coolant around through the same circuits.

I'm afraid it is only Nescafe instant so ...
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Expedition Leader
Awesome info...Thanks a bunch. Some reason I was always thinking the water was wandering through the block..yuk! Your way not only explains it well but includes a DIY diagram!:wings:

I'm afraid it is only Nescafe instant so ...
Guess even this will take care of the one to many Fosters Oil cans the night before.?.:elkgrin:


Expedition Leader
Welcome, Flasher Pete! That's a great looking truck.

The arguments in favor of propane or some other form of compressed natural gas over the diesel cooktop include:
-- fast start up
-- more delicate / more accurate control of cooking temperature
-- quick shut down, interior of the camper is not heated more than necessary
-- RV natural gas cooktop is cheaper that diesel units, and easier to find parts to repair

Arguments against natural gas for cooking
-- combustion gases stay in the camper, should provide a vent or crack open a window
-- small risk of explosion if gas leaks into the camper
-- not always easy to find the local natural gas refill station, it's often on the outskirts of town for safety reasons
-- each country seems to have its own idea about the adapter needed to refill the gas storage tank, and without the right adapter it's often impossible to refill

Some travelers use a diesel cooktop inside the truck, and a portable natural gas burner for cooking outside.
Gotta have the Java!:coffeedrink:

If I can ask a really NEWB question...How does the water, the potable water specifically, get heated via the engine without coming in contact with antifreeze? *embarrassed...*
The heat exchangers are typically high quality stainless stell. This isn't something done inexpensively due to mixing toxic antifreeze with potable water. If the hot water heater is heated by the camper heating system's non- toxic antifreeze can be used as an additional safety factor. Hot water has been made on boats from engine heat for years and safety aspects are well understood.

I've never heard anyone talk enthusiastically about a diesel cooktop, but it is certainly a logical choice for international travel for the reasons mentioned. A diesel cooktop is pretty much like a crappy electric stove - perfectly usable but no one who cooks with it loves it. Cooking with diesel smells of diesel outside the the camper. Not strong, but ode de bus station is not exactly gourmet.

I like having propane, but not for heat or refrigeration. If the critical systems don't run on propane much less is used. Plus there isn't the pressure of finding it in wild or unfamiliar areas.

The disadvantage I see with a "single fuel diesel approach" is not only the cooktop but the diesel generator. I would rather have solar panels and a little tri-fuel generator. Not arguing that an all diesel design is a mistake, just that it may seem a clearer choice in theory than in practice.

Tony LEE

International Grey Nomad
Some travelers use a diesel cooktop inside the truck, and a portable natural gas burner for cooking outside.
Yes, we also carry a single burner camping stove fuelled from the disposable butane cartridges. It is in the outside locker and used when we are travelling and need to heat something up for lunch.
I've spoken to two owners who have diesel fuel stoves in the their trucks, and both said that although it was a bit slow to start up, it worked great with good heat control. I've never heard of anyone complain about the exhaust smell - but never asked them either - are you speaking from personal experience dzzz?

I plan to have a diesel fuel stove in mine for the overseas travel, and will most likely go with a small diesel generator as well as solar - having a single fuel source far outweighs the negatives in terms of weight and cost in my opinion

I don't like the idea of LPG inside - over here in Australia you need to have gas detectors, a minimum size vent etc if you have lpg inside. The storage compartment must comply with certain regulations, and you need a certificate from an "authorised person" for the installation.

The outside stove will a normal camping stove and or gas barbeque so I can swap it over to the various systems of lpg tank for each country if necessary. LPG is also very hard to find in some places - so relying on it as the only source for cooking is not possible.
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Reviving an old thread here...

Has anyone used a diesel cooktop (specifically a Webasto with the high-altitude setting) at altitudes over 10,000 feet (3000m)? We're building a sportsmobile-like van in preparation for a trip through South America.

Ideally I'd like a webasto cooktop and a dual-top for space and water heating for all of the 'single fuel' reasons mentioned above. But that stuff is expensive, and I'd be disappointed to not be able to use it for a portion of the trip.

The other option is diesel air/water heating and LPG for cooking, if for some reason the dual-top works better at altitude than the cooktop. A good sized propane tank would probably last a long time if you're only cooking with it, so that we may only have to refill it 2-3 times over the course of a year. But that also entails installing whole separate fuel system.

One 8.5kg propane cylinder was 25-30% full after 6 months continuous use in my camper powering the stove. Two 20 lb cylinders should last ~16months for just cooking.