Webasto / Espar: High Altitudes Usage

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The Webasto / Espar air heaters should be adjusted for high altitudes if the majority of it’s time is spent above 5000-6000 feet. As the altitude increase, the concentration of oxygen reduce and the mix of fuel/oxygen become too rich in fuel. This could lead to debris accumulation (a.k.a. coking or carbon) and loss of performance / malfunction. We know, because we had that issue with our Webasto and after a while it just wouldn’t start at all.

It is interesting to note that the Gasoline models are more prone to carbon accumulation than the Diesel models! This is counter intuitive because gasoline is more refined than diesel, but TechWebasto said it’s because “gasoline is less energy-dense than diesel“. We believe it’s true, because we have the Gasoline model and we had carbon issues quite fast…

 

For the Espar, the solution is to add a high altitude kit. Here is the installation manual.

“The kit automatically adjusts the fuel pump rate in relation to increasing altitude. As the altitude increases the fuel pump rate decreases. The High Altitude Kit adjusts fuel pump rate at all altitudes beginning at sea level.”

Espar High Altitude Module

Espar High Altitudes kit. Buy from Amazon

 

 

For the Webasto, there is no physical part to add; the unit must be programmed for high altitudes.

You can have it adjusted by a Webasto dealer, or it can be done using the rheostat:

Webasto Rotary Rheostat

Webasto Rotary Rheostat. Buy from Amazon.

If you’re having the SmartTemp or the MultiControl, you will have to buy (or borrow) a rheostat to make the adjustment.

Webasto SmartTemp

Webasto SmartTemp

Webasto MultiControl

Webasto MultiControl

 

Here is the high-altitude adjustment procedure:

(the procedure was confirmed by TechWebasto and it worked for us)

 

Changing the Webasto heater for high elevations (5,000ft and MORE) using the rheostat

On the main wiring harness, there is a wire that is used to make the CO2 calibration. Depending on your heater/controller model, the CO2 calibration wire is either brown (look for a 2-wires pigtail; there should be one brown wire and one green wire) or is either grey/red (look for a pigtail with only 1 wire; it’s close to the “Diagnose/Thermocall/Telestart” pigtail).

CO2 calibration wire. It should be located at the extremity of the harness (far from the heater unit itself).

The rheostat is connected to the pigtail labeled “USER POTENTIOMETER”. It should be located near the heater unit itself.

  1. Connect the CO2 calibration wire to ground (we connected it to our house battery negative, because our heater is connected to our house battery).
  2. Turn the heater control knob to 12:00 (or even 1:00 if you are at very high altitude 10,000ft plus)
  3. After a few moments (the heater will fire up and run for a few minutes), the LED on the heater control knob will begin to flash.
  4. Turn the heater control knob to 9:00 (or even 8:00 if you are at very high altitude 10,000ft plus)
  5. Keep the heater running with the control knob set to 9:00 for 3 minutes.
  6. While the heater is running, remove the CO2 calibration wire from ground.

Now the combustion fan is set to run faster, thereby creating a better combustion mixture for high altitude and less oxygen.

 

At that point, a Webasto dealer will actually check the adjustment by analyzing the exhaust gas when the heater is running; they have a machine that tells if the oxygen/fuel ratio is correct for the current altitude. We don’t have such a thing, but TechWebasto strongly recommended us to borrow an “Automotive Exhaust Gas Analyzer” from an auto service shop. We’re constantly changing elevation so there is no way to have the perfect setting, but at least the “Automotive Exhaust Gas Analyzer” gives a baseline for the adjustment (so it’s not done totally blind).

 

The tech said you can change it back when at sea level, but also said it was unnecessary, as the reduced fuel will not cause damage at sea level, just a lower heat output by 100-200 BTU/ hour at the maximum setting. He said that running it lean at sea level will also help to keep the combustion chamber clean. The Webasto Air Top 2000 ST/STC has a max BTU/h of 7000 so you are only losing at most 3%, and you are also reducing your fuel use, albeit marginally. Also, the system has Stepless temperature control, so you can feel free to turn it up 3% to regain your “lost” output all the way up to 97% output.

 

Changing the Webasto heater back for normal elevations (5,000ft and LESS) using the Stock Dial Thermostat
  1. Connect the CO2 calibration wire to ground (we connected it to our house battery negative, because our heater is connected to our house battery).
  2. Turn the heater control knob to 9:00
  3. After a few moments, the LED on the heater control knob will begin to flash.
  4. Turn the heater control knob to 12:00
  5. Keep the heater running with the control knob set to 12:00 for 3 minutes.
  6. While the heater is running, remove the CO2 calibration wire from ground.

Now the fuel pump should be set to deliver the stock amount of fuel, thereby creating a better combustion mixture for low altitudes and more oxygen.

 

 

 

 

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ABOUT US

Hello! We’re Isabelle and Antoine 🙂 In 2017 we sold our house (and everything in it), quit our engineering careers and moved into our self built campervan. We’ve been on the road since then and every day is an opportunity for a new adventure; we’re chasing our dreams and hopefully it inspires others to do the same!

 

 

CHEERS!

 

 

 

You might be interested in these articles:

Webasto Air Top 2000 – How To Install a New Burner Following Carbon Buildup

 

Webasto Air Heater Installation

 

Webasto Air Heater Noise Reduction

 

 

17 comments

  1. Comment by Christian

    Christian Reply March 26, 2018 at 12:38 pm

    This heater installation has been quite the project.
    Did you guys have any trouble connecting your rheostat to the wiring harness that came with the Smart Temp controller?

    I just ordered a rheostat, but it appears to want a 4 pin female control connector.
    There isn’t anything like this on the wiring harness that came with my unit (that connects to the smart temp controller).

    • Comment by Antoine

      Antoine Reply March 27, 2018 at 10:41 am

      Hey,
      We connected the rheostat to a pigtail labeled “User Potentiometer”; ours was located near the heater unit itself (under the seat):
      Webasto Rheostat Pigtail

      Hope that works!

  2. Comment by Christian

    Christian Reply March 13, 2018 at 1:24 pm

    I just gave it a try and wasn’t able to get it to work. A would get an error code (“Fault F00”) after a few minutes when I started the SmartTemp with the brown wire grounded.

    Apparently I’ll either need to buy a rheostat, or find a dealer who can adjust the unit.

    • Comment by Antoine

      Antoine Reply March 13, 2018 at 1:28 pm

      Thanks for reporting back.

  3. Comment by Christian

    Christian Reply March 12, 2018 at 12:34 pm

    Hey, I’ve been going through my own struggles installing my Webasto. I finally got it working, and was about to buy a rheostat to do the high altitude adjustment.
    I did some searching and found this:
    https://www.thesamba.com/vw/forum/viewtopic.php?p=7497254&sid=5f685948e349b8b7fbbfdddd8edf272a#7497254

    It sounds like you can make the same adjustment with the smart temp controller.
    I haven’t tried this yet, but I’ll give it a go and report back.

    • Comment by Antoine

      Antoine Reply March 12, 2018 at 12:47 pm

      I’ve seen the instructions for the smart temp, but some people say it doesn’t work… I don’t know anymore, please let us know!!

  4. Comment by Steve

    Steve Reply October 4, 2017 at 10:40 pm

    Do you have experience with the Espar D2? If so, how would you compare the noise issues between the Espar and the Webasto?

    • Comment by Antoine

      Antoine Reply October 4, 2017 at 11:12 pm

      They’re almost the same, no difference from what I know. Source: internet & I finally heard an Espar running 2 weeks ago!

      Antoine

  5. Comment by Jeremy Morgan

    Jeremy Morgan Reply August 24, 2017 at 11:01 am

    Reading through their literature, it sounds as though the Multi-control should have the ability to put the unit in to the high altitude mode. There is a manual switch which is available to do this for the thermostat control options but the install manual states that the switch isn’t for use with the W bus connections (multi-control). I emailed Webasto UK in hopes that it is as easy as a setting on the multi-control.

    Those directions from the Samba post appear to be using the CO2 calibration procedure to effect the same change. It appears that those directions are for an Airtop 2000 ST, although they should work with the STC only replacing the brown wire with a green/red wire.

    We live in CO at 7,500 feet and many of our adventures are higher than that, hence my need to figure this out. Thanks for all the information that you guys have published, your site is one of my go-to resources. If you ever find yourselves in CO I’d love to buy you some beers and maybe show you some secret pow stashes ;).

    If I figure anything out I will let you guys know.

    • Comment by Antoine

      Antoine Reply August 24, 2017 at 2:55 pm

      Secret pow stashes and beer? This is all we need in this life! We’ll let you know when we’re around! Thanks!

      • Comment by Jeremy Morgan

        Jeremy Morgan Reply August 24, 2017 at 11:07 pm

        It appears that there may be more readily available tech support in NA soon. I came across a AT2000STC_USA operations manual on the tech webasto site. It’s release date was August 7th, 2017, so hopefully the tech support people at Webasto USA will soon be of some use for the STC model heaters.

        • Comment by Antoine

          Antoine Reply August 25, 2017 at 7:14 am

          OMG this is such a GREAT news!
          As we just hit the road, I can’t take the Webasto issues we had out of my mind; this is the single part of the conversion that worries me the most. No Webasto = No POW!

          Let’s hope support for the STC is available this winter!!
          Here is the tech Webasto link: http://techwebasto.com/documentation/heater/cargoapp/at-2000-stc.html

          Thanks for letting us know!
          Cheers!

  6. Comment by Jeremy Morgan

    Jeremy Morgan Reply August 24, 2017 at 1:06 am

    have you guys been able to figure out how to put the heater into high altitude mode with the multicontrol?

    • Comment by Antoine

      Antoine Reply August 24, 2017 at 6:30 am

      Nope, we’re still in the flat lands (and summertime) so this will have to wait… Our guess is that we will have to do it at a Webasto shop; we’ll keep you updated!

      Have a good one,
      Antoine

    • Comment by Antoine

      Antoine Reply June 8, 2017 at 6:36 pm

      Could not find any info about that timer, unfortunately 🙁

  7. Pingback: Webasto Air Heater Noise Reduction | FarOutRide

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