Diesel Heater Installation - 9 Things to Do

We will start by saying this. This diesel heater installation article is not to be used as instructions to install your diesel heater. Reading and understanding the diesel heater manufacturers installation instructions is a MUST. The instructions are comprehensive and should allow for an easy, uncomplicated installation in most cases. You can find installation manual downloads in our technical library. If you are not confident after reading the instructions consult a professional installer, such as a van conversion company or automotive engineer.

Update: Since writing this article Butler Technik have introduced a new air heater turret mount plate. The new turret plates, known as the "Mount Pro" series, are designed to make the connection of exhaust and air intake more secure and easier to access for maintenance. You can read more about these below, or visit the mounting accessories department to view and purchase.

9 Things You Should Do

There are a lot of dos and don’ts as every installation will be different, but a brief list would be:

  1. Do, cut electrical power supply leads to length to minimise voltage drop
  2. Do, connect to leisure battery, do not connect to vehicle starting battery
  3. Do, position the exhaust gas pipe in such a manner that exhaust gas cannot enter the vehicle, be drawn in by the vehicle's fan or by the heater's fan
  4. Do, draw combustion air from the outside the vehicle, not from the passenger compartment or trunk
  5. Do, arrange the air intake in such a manner that it cannot draw in any exhaust gas.
  6. Do, route exhaust pipe directly outside through the floor (using suitable mounting plate).
  7. Do, always point exhaust pipe and combustion air pipe toward the rear of vehicle, never towards the front.
  8. Do, install a CO detector when you are installing your heater.
  9. Do, install thermostats in the area you are warming, and at the height you want to measure the temperature.

Below you will find a summary of the installation instructions for the Eberspacher Airtronic D4S diesel heater into a campervan. Again, we insist the manufacturer’s instructions must be read thoroughly before proceeding with any installation. If you have any doubts about your ability to install the heater you should consult an experienced person.

Where to install your diesel heater

Locating the heater unit will depend on the configuration of your campervan. There are some basic rules to follow when selecting a location.

Install in the passenger area or boot of your vehicle. If it is not possible to locate the heater unit internally it is possible to install the heater unit externally. Installing internally has the benefit of protecting your heater from the elements and possible theft.

Check for clearance where the exhaust and air intake will exit the vehicle. They must not obstruct or interfere with any of the vehicle’s components and the exhaust pipe must be away from any surfaces which will be affected by heat, such as fuel lines, fuel tanks, and electrical wiring.

diesel heater installation

Positioning the Heater Unit

diesel heater mounting angles

It is recommended to install the heater unit in the ‘normal position’ which is with exhaust outlet at the bottom and the heater body at flush to the floor. If this is not possible there is a maximum recommended allowance of 30 degrees tilt from end to end. The heater unit can also be mounted on its side if necessary, ensuring the glow pin is at the top of the heater, admittedly this is not usually required for vehicle installations.

NOTE: If necessary, the wiring harness can be moved to the left or right side of the heater body. See the manufacturer’s instructions for details.

Mounting the Heater Unit

The most popular and easiest method of mounting the heater unit into vehicles is by way of a heater turret mounting plate. This allows you to cut just one hole instead of several and the mounting plates also compensate for uneven surfaces, such as corrugations.

Heater turret mount plates come in assorted sizes. The height required is determined by the thickness of the surface to which the heater is to be mounted. The most popular sizes supplied by Butler Technik are 30mm and 60mm.

If you prefer not to use a heater turret mount you can always mount the heater directly to the surface, but this is more time consuming, and you may need to deal with the issue of uneven surfaces. Instructions and templates are provided with the heater.

diesel heater turret mounting bracket
easy install Mount Pro diesel and petrol heater turret mount

For easier installation we recommend the Butler Technik Mount Pro turret mount plate. Designed to work with Eberspacher (Espar), Webasto and most Chinese diesel and petrol heater brands. The unique cut-out allows easy access to exhaust, fuel line and combustion air intake clamps, ensuring you get a tight and safe fit for these important connections. The range includes 30mm, 60mm, 75mm and 100mm turret depths to suit varying floor and insulation thicknesses.

The Exhaust Outlet

diesel heater exhaust installation

Burning any substance produces toxic gases. In the case of diesel heaters Carbon Monoxide and other dangerous gases are produced. It is therefore essential that the exhaust pipe is positioned correctly to avoid harm. The exhaust MUST be able to escape into the atmosphere and not be able to enter the vehicle.

The exhaust pipe should not protrude from the beyond the vehicle as it can get to temperatures of 400 degrees Celsius (752 degrees Fahrenheit). It is also important to take into consideration if you have an awning or a tent that connects to your campervan. You won’t want the exhaust in this enclosed space.

Exhaust should be pointing away from oncoming air and angled downwards to drain off condensation to avoid corrosion. If that is not possible a 5mm hole should be drilled through the lowest point of the exhaust pipe to allow the water to drain.

There are further requirements to follow specific regulations, and these can be found in the manufacturer’s instructions.

Moving the Warm Air

Now we come to moving the air, so you are safe and warm and best heater performance is realised.

Combustion Air Intake

The air intake to the heater must be drawn from outside the vehicle, not from within the cabin or passenger area. There are small arrows engraved that show the direction of airflow.

The air intake tube is situated so as not to draw in any exhaust or air from the heater, and it must face away from oncoming air. Point it towards the rear of your vehicle. This ensures that no obstructions become lodged within the air intake and damage the heater or cause a health hazard.

diesel heater air intake installation

Diesel Heater Air Ducting Installation

diesel heater ducting installation

The air ducting can get hot so be careful to install it where it will not cause damage or injury. Avoid placing it against surfaces that are likely to be affected by radiant heat. The air outlets must be positioned so they do not blow hot air directly on skin.

Fuelling The Diesel Heater

diesel heater fuel pump installation

CAUTION: As with any flammable fuel care must be taken when working that you do not endanger yourself of others. Do not smoke or work where there are exposed flames or live electrical cables. Do not inhale the fumes and work in a well-ventilated area.

It is advisable to read the full installation instructions for connecting the fuel to your heater. There are important considerations to observe. The information below is basic and should not be used as instructions. The manufacturer’s instructions have detailed diagrams and drawings, and you must read these to get full understanding and confidence to install your heating system.

Install the fuel dosing pump where it will not be exposed to excessive heat and where it is protected from direct impact.

Ensure that the fuel line is located to avoid kinks and twists. There must not be any chance that the fuel line will be exposed to hot surfaces such as exhaust pipes or silencers. You must also ensure that a fuel leak cannot lead to pooling of fuel or vapours.

Always use the proper clamps and supports when connecting fuel lines. These are supplied with the heater. If you need to replace any parts purchase genuine replacement parts. When connecting plastic fuel lines always use rubber connectors.

When cutting fuel lines, you should use a sharp knife. Do not use scissors or any other tool which could lead to 'no start' fuel blockage errors.


This article IS NOT an installation manual. Your diesel heater will have a handbook with instructions for installation and use of your heater.

If you are going to install the system yourself it is most important that you read and understand the procedure BEFORE you begin. Do not leave reading the instructions until after as this could lead to extra expense and loss of your time.

If you do not have a heater handbook with your system you will more than likely find a downloadable version in our Eberspacher and Webasto technical library.


At Butler Technik we take pride in supplying first class after sales support to our customers. If you have any pre-sale inquiries, you are always welcome to contact us with your questions.