Installing a Webasto Heater in a Van

I spent the winter in Pennsylvania helping a friend build a van. In order to prepare for the cold PA weather, I purchased a Webasto Air Top 2000 heater (diesel version). The biggest difference between Webasto and Espar that I could find was the ability to manual adjust for altitude in the Webasto. Espar sells an attachment for auto-adjustment. I bought mine on Ebay for around $900. It came as a kit with everything I needed and included the optional smart thermostat.

To use the least amount of fuel possible, I decided to create a duct and have the warm air toward the ceiling return to be heated by the Webasto and have the outlet air low towards the floor. It’s important to have the return air duct have a larger opening than the outlet air. I wanted to make the return air duct fit behind the passenger seat so I had to make it very wide increase the opening size.

Made sure to cut the holes before building the partition. It would have been much harder will a big wall in the way.

To see the full post about the partition build read DIY Sprinter Van Partition

Like most people, I decided to install the heater under the passenger seat. It fit perfectly. The kit came with a template for the holes.

The seal here is very important to prevent any CO from coming inside the cab. The metal must be very clean and flat before installing. Even if you don’t install a heater, it’s a good idea to have a CO detector.

This is the smoke and carbon monoxide detector I use. It has a voice alarm!

Once the spot is smooth and clean, the holes were drilled out and painted to prevent rust.

There was a good spot to run the wires under the little mat. I plugged a large hole with a cork.

Underneath, the metal hoses were connected. The lines must not point towards the front. Both of them are facing downward. It’s also important not to put them in a location where mud cannot splash inside.

I covered the white box with some plywood. This box isn’t air tight and I’m okay with that. Some fresh air from the cab will mix with the return air from the living area. Most of the intake air will still be recycled warm air.

Now there are two different ways to do this. You can either tee into the existing fuel line and add the fuel pump there or you add a new tap into the tank and run a new fuel line. I opted for adding my own tap because I had worries about starving one of the fuel pumps if I was driving with the Webasto heater on. If you just tee into the existing fuel line, there’s no need to drop the fuel tank. Dropping it was just a matter of disconnecting everything, making sure it was almost empty, and lowering it with a hydraulic jack. It only took a few minutes.
I unscrewed the top of the tank and pulled out the fuel pump module. This is a scary step because there was so much dirt and crud on top of the fuel tank that I didn’t want to end up inside the tank. I dumped the fuel in the reservoir into a bucket.

The plan was to find a place to put this through the top:

This seemed like the best spot. Again, I had to make sure none of the filings from the drill ended up in the reservoir.

The under side had to be modified with a dremel tool to make it fit properly.Everything for the tap was assembled. The tap was cut off a little high so I wouldn’t wake up to an empty fuel tank. I find at this length, the heater will shut off when I have a little less than a 1/4 of a tank. 

The tank was put back in place. This is the fuel pump and filter that comes with the package:

Then it was just a matter of attaching the fuel lines to the fuel pump and heater. The fuel pump was mounted here. The heater works great. I’m very happy with the upgrade. The installation manual goes into a lot more detail than I did here.

Here’s a demonstration video I made:

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  • David Hooper

    Very helpful photos, especially the drilling location in the sender unit!

  • Mike

    Hey thanks for the post! I purchased the exact same kit from eBay as you. Did you use both wiring harnesses? The smart temp controller came with a wiring harness but I don’t see how I would use both harnesses?