Fitting a diesel heater

Fitting a diesel heater

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With the winter already at our doorstep it’s time to talk about how to heat up our motorhome.
At some point the manufacturer’s gas heater has been removed, leaving us without any heating source on board.

One of the most popular choice (and our as well) is to install a diesel heater.

What's a diesel heater?

A diesel heater is basically a combustion burner which uses diesel as a fuel to heat up the surface of heat exchanger.
At this point an internal blower (a fan) drawn the air from around the heater, forces it over the heat exchanger and blow it out nice and warm through one or more air vents.

This system has been used for years by lorry drivers to keep the cabin of their trucks warm during the rest stops and it’s still the main purpose for these devices.

For years the whole market has been dominated by mainly two german brands: Webasto and Eberspacher. They still are the best in class when it comes to diesel heaters but in the last few years other Chinese brands have taken on the market thanks to a really affordable price (starting at just over £100).

Why a diesel heater?

Diesel heaters are very efficient. They don’t need a lot of power to run and use a very low quantity of fuel.

Over the years we had the opportunity to use gas and electric heaters as well but so far nothing could compare with a diesel one.


Chinese diesel heaters are quite cheap and is no surprise that few parts that come with the kit are worth an upgrade.
All the parts we’ve used are available online and is worth to mention that several parts are compatible with Webasto/Eberspacher.

    On our motorhome the insulated floor is 6cm thick. That means that the exhaust pipe (and burner’s air inlet) need to run through it before to get outside. In order to protect the floor and create a sealed exit for the exhaust we bought a turret plate. It works exactly as the cheap mounting plate provided with the heater but has a way better quality and it’s much safer. 
    Depending on what heater you buy, you may find a green or a white fuel line.
    Usually the green one (the one that was with our heater) is the worst and it’s likely to split. The white fuel line, instead, is generally good and we used it for more than a year on our old campervan without any issues.
    This time though, since the fuel line is going to be around 4m long, we’re gonna use a good quality braided fuel pipe from the tank to the pump and use the white pipe just for the last part, from the pump to the heater.
    The exhaust pipe is one of the most important part of the heater as it can be very dangerous in case of a leak.
    The pipe that came with our heater was too short and , to be fair, the quality was pretty bad too.
    We upgraded it with a 2 layers stainless steel one, which can be cut to size if you need to.
    At the moment we’re not using a muffler (the one that was in the box didn’t really make any difference) but you can find online some better quality ones which will actually help to reduce the noise.


On our motorhome has been relatively easy to find a place for the heater.
We decided to have it under the seating area, inside one of the benches. Using a tee we’d been able to have a vent in the living area and one in the bathroom.

The first step of the installation was to drill the floor and fit the turret plate in place using 4 M6 bolts/nuts. Don’t forget to use some high temperature resistant silicon to seal the turret avoiding any chance for the fumes to get inside in case of a leak from the exhaust.

At this point we mounted the heater on the plate replacing the 4 studs we found in the kit with 4 M6 stainless steel bolts.

With the heater in place was time to connect the air inlet (for the diesel burner), the exhaust and the fuel line. We started with the air inlet, ideally you want it in a covered position to avoid any dirt you might pick up from the road to create damage/issue to the heater. In our case the safest thing was to direct it towards the middle of the vehicle because unfortunately with the van’s exhaust so close we didn’t really have a lot of options.

After that we focused on the fuel line. We’re gonna talk later about the whole line, for now we connected just the pipe going from the heater to the pump and the reason is simple: it’s easier to do it now without the exhaust pipe in the way.

The last bit we needed to fit was the exhaust. There are few tips about it that is worth to remember:

  • avoid as much as possible any hard bend and keep it always going downwards. That’s because any condensation that might be formed inside the pipe needs to find his way out otherwise is gonna create rust that will eventually lead to a leak;
  • if you’re using the muffler that come with the heater make sure to have the drain hole (yes, there is one!) pointing down;
  • make sure that the exhaust is facing the back of the vehicle and that is pointing out of it to avoid fumes to collect underneath.

That’s how we managed to route ours:

As I said before we’re not using a muffler at the moment but that could be something we’ll look at in the future.

Now let’s come back to the fuel line. In our installation we didn’t feed the heater from the vehicle’s fuel tank but we decided to rely on a separate tank just for this role. That’s entirely up to you. We chose to not mess around with the main fuel tank so we added the 10l tank which came with the kit in our gas bottle locker.
This way it’s easy enough to refill and, most important, is not inside the living area, avoiding any possible unpleasant smell.

There is an upgrade though that you can do on the fuel tank. The connection provided in the kit is meant to be fitted at the base of the tank but in this way in case of a leak (unfortunately it’s not rare) you may end up spilling litres of fuel.
We bought a stand up sender unit which allows you to drill the top of the tank and use a pipe to reach the fuel at the bottom. This way if we ever need to disconnect the pipe from the tank we won’t need to worry about the fuel in it.   

To fit the tank in the gas bottle locker we used 2 straps tie and then we ran the fuel pipe through the floor and across the whole camper to reach the fuel filter, this one, in fact, needs to stay as close as possible to the pump and is positioned right next to it.

The last remaining bit is the fuel pump. It must stay at a specific angle (30/45 degrees) to work in the best possible way.
One thing to notice is that usually they are quite noisy. There are different methods to hold the pump in place to help reduce the noise, one of the most effective is to hang the pump with 2 zip ties and keep it far from any surface that can amplify the ticking noise.
To be fair in our case the noise is barely hearable inside so we didn’t bother to try different solutions.  

At this point all was left to do was the electrical part.

The wiring loom is pretty simple. There is a wire (+12v and  earth) to connect to the leisure battery, a plug for the fuel pump and one for the controller. That’s it!

When we chose where to fit the heater we made sure it was as close as possible to the leisure battery, in fact we’re less than 2m away.
Before to connect the wiring to the battery, though, we have to connect the fuel pump.
Now, that was a bit more tricky because the pump is under the floor and not inside the motorhome.
Unfortunately there wasn’t any hole nearby we could use to run the wire through so we needed to drill a new one.

With the pump now connected it was time for a little test. We plugged the controller in and we connected the battery: time to fire it up!

It took few minutes to bleed the system and having some hot air coming out the heater but it started at the first attempt with no smoke or other issues: great!
We switched it off and we waited another few minutes for the system to complete the cool down procedure.

Now that we knew everything was in order (and after checking underneath for any fuel leak) we started to route the warm air towards the 2 vents, the first one under the seating area and the second one in the bathroom. 

The job wasn’t hard at all and that’s the final result:

With everything now in position and working as it should we moved the controller to its definitive position.

One last thing worth mentioning is the importance of having a CO detector inside the motorhome. It’s a really cheap device and I can’t stress enough how important this is when using a diesel heater.
We put ours on the wall next to where the bed is going to be during the night. 

That’s it for our installation! We’ll update this post in case of future mods.

For more info check out the video we posted about this on our YouTube channel and feel free to write to us if you have any questions.

Stay warm!

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