Caravan Diesel Heater Installation; a step by step guide

With our lap of Australia approaching fast, Sarah and I were debating whether to take our diesel heater with us, or leave it at home. For the last couple of years we’d kept it as a portable diesel heater, and on our last 3 weeks to the Pilbara we intentionally left it at home, to see if we’d actually regret it or not.

Originally we both said not to bother with it, but after a lot of thought I decided we should take it, and install it permanently. We already had the unit, it wasn’t going to take up much extra room, and for a days work it would be greatly appreciated if we needed it. 

I was dead keen on not having it as a portable unit for long term travel, so set about stripping it apart and mounting it permanently. In this post, we look at your typical Caravan Diesel Heater Installation, and what you need to know.

If you don’t know much about diesel heaters, we go into them below, but essentially they are the only option for off grid heating (except gas heating) as you cannot get a suitable 12V Heater.

EDIT – This was one of the best moves we’ve made, with it being appreciated so much more than I ever thought possible in places like the Victorian High Country, and even parts of NSW.

Getting the diesel heater and components

If you buy a caravan diesel heater today, you’ll get a kit with everything in it. If you have a portable unit like we did, there will be things that you’ll be missing, and you’ll have to buy/make up the missing bits. Alternatively, it might be easier to sell the portable unit and buy a new one designed for installation.

For us, we were missing the longer runs of fuel line, clamps to hold it against the chassis, vents in and out for the heater, shroud to protect the flooring and I knew we’d be able to buy them elsewhere, or make it up as needed. 

If I did it again though, I’d probably sell the portable heater, and purchase a dedicated diesel heater for a permanent install. I spent about $100 buying extra parts that would have come in a kit, and it took a while to find them (the heater outlets I had to buy online and hope they arrived in time to leave).

The fuel line was a challenge to find, with no one carrying anything small enough. I ended up getting it from Stihl, along with a fuel filter that never came with the unit.

I also had to make up a turret plate as the portable unit didn’t come with it, but most of the permanent setups do. If I didn’t have access to material, tools and a welder at work it would have made life far more challenging.

Make sure you get the right size heater

Please, do yourself a favour and make sure you are getting the right size heater. Our portable unit was a 5KW, and we installed it, but its too big when permanently mounted (as it recirculates the air) and makes our camper too hot.

You can get 2KW heaters which are much smaller, and more suitable for most caravan installations.

A 5kW heater is 38cm long, 13.5cm wide and 13.5cm tall. 

A 2kW heater is 32.5cm long, 11cm wide and 11cm tall 

Get a CO monitor

Promise me that you’ll head to Bunnings and pick up a $40 CO monitor, and keep it in your Caravan. These will detect any harmful gas (which should not be produced by the diesel heater unless its incorrectly installed, or it breaks), and wake you up. People have died in their Caravans from CO poisoning; don’t become a statistic.

What do you need to install a diesel heater?

A Caravan Diesel Heater Installation can be legally done without any qualifications, and as long as you are handy on the tools and have some basic gear, you can get it done fairly easily. A diesel heater needs 3 things – air, diesel and power, and hooking it all up is fairly straight forward.

In terms of tools, the basic hand tools along with a drill, file or rasp, and various drill bits make life easy. I will make a point of saying that this is a fiddley job, and you should expect to spend a fair chunk of time on it.

It took me about 12 hours to do the full install, with a lot of that time pondering the best way to put it in, mount things and what order to get it done.

Caravan Diesel Heater Installation process

Find a suitable location for the heater

Before you do the installation, you need to spend a fair bit of time measuring and checking how the heater is going to fit. The normal way of installing a diesel heater in a caravan is to cut a hole in the floor where the shroud drops in, and your exhaust goes out (and combustion fresh air comes in). 

In a Caravan, most people install the diesel heaters under a seat, or under the bed. You need room for fresh air to be sucked into the heater, and for the warm air to be ducted out, usually into a vent that comes out through the edge of the bed, or seat. 

Don’t put it too close to other items, but the most important thing is to ensure when you cut a hole in the floor there is nothing underneath that is going to get in the way.

I started off looking at the best location inside, and then when I hopped under our camper realised that my options were limited by a number of cross beams running in different directions.

I then took some measurements inside, and went underneath and drew a diagram of the different beams, and went back inside to mark it onto the floor.

From there, I could identify the positions that would work, which were really limited without obstructing the door, or hugely reducing our already tiny storage space. 

Find a suitable location for the diesel tank

Your diesel tank also needs to be mounted somewhere, and there’s a few options. A lot of people put them near the drawbar, or on the edge of their front toolbox, but I’ve seen them on the rear of the van too.

It’s a good idea to cover them, or put them in a box as the UV rays will kill the plastic over time. For us, we had a couple of hatches at the front of the van that are not waterproof, and this meant we had a decent location.

Ideally, put the tank on the same side as your vehicle fuel fill point, so you can do both easily at the fuel station.

The diesel tank can actually be the most frustrating thing to mount, as you have to find a spot that works well. Don’t put it inside your van; if it leaks, or you spill anything refuelling you will regret it for a long time.

Work out how you are going to plumb and wire it together

Once you know where the tank and heater are going, you have to be able to get the diesel from one to the other, and power to the heater itself.

Most people run the hoses along the chassis with P clamps holding it in place, but put it in a location that isn’t going to get taken out by a stray branch or peppered by rocks. 

You can take power from a variety of sources, but know that they do draw 10 amps on start-up, and you need a decent power supply.

The pump needs to be installed between 15 and 30 degrees, and if you can have the fuel tank slightly higher then its a good thing.

I had to extend the wiring to the fuel pump as it was too short, and I needed to cut it off to feed it through a smaller hole (that I drilled just next to the turret plate).

Cutting the hole

When you are happy with everything above, and you’ve measured twice, I suggest you drill a tiny hole – 2 – 3mm in the centre of your cut out, and hop underneath and check its all correct. If it is, go for your life. If it’s not, you better seal that hole up and mark it out again.

If you have a hole saw that suits the turret, this is the best option. If you don’t (and I didn’t), just drill a series of small drill holes around the circle, and then use a hacksaw blade and file to finish it off. 

Mount the heater and plumb it up

From there, its just a case of dropping the shroud in (with some silicon on the bottom), bolting the heater down, installing the exhaust pipe (make it face towards the back of the van) and the fresh air intake (away from the exhaust!).

Plumb the hot air vent out, and connect it to your vent in the wall that you are using, and a fresh air intake if needed. We’ve just got a vent that allows camper air to be sucked into the box where the heater is mounted, and haven’t worried about any ducting on this end.

Connect the fuel line up, secure any lines under the caravan out of harms way, and use split conduit on everything if possible. Seal up any holes with silicon, and then get ready to test it out.

Prime the heater and test it out

Your diesel heater should come with instructions to prime the unit, and its generally fairly easy to do this, whilst you watch the fuel move along the line (if its clear!).

In our case, you press two buttons and then use the arrow to make the pump come on.

We ended up with nearly 4 metres of hose, and it took a number of goes to get it to prime. At a guess, I’d say around 15 minutes; the fuel runs at a very slow rate and will eventually splutter out the line near the inlet to the heater (leave it disconnected).

When its primed, fire it all up, and give it a whirl! 

Changing settings from Hz to Celcius (or vice versa)

These Chinese Diesel Heaters will either run off Hz, or Celcius, and you can wind them up or down by adjusting this. In the past we’ve always run it off Hz, as the unit was outside and it would never read the internal temperature.

I will be doing some more testing with it on Celsius, which is supposed to regulate the heat output of the heater based on the temperature its reading. You can change between the two settings by pressing two buttons at the same time, and we’ll give it a whirl at 15 degrees, or even lower. 

My initial thoughts though, is that the heater is now too large for our camper trailer when it recirculates the heat, and without custom tuning it, or opening windows, we have limited options!

I’ve now confirmed this, with the temperature set at 8 degrees (as low as possible) and the camper still getting warmer and warmer.

Diesel heaters are amazing

There really is no way of explaining just how good diesel heaters are. Yes, they tick and can be annoying depending on how you mount them, but the heat output, low fuel consumption, price and ease of use make them pretty amazing.

There would be tens of thousands of Chinese Diesel heaters in use around the globe, and they are generally pretty reliable. 

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