Webasto-Air-Top-2000-Install-New-Burner-Carbon-Buildup---Heading-(1200px)

We often say that our Webasto air heater is one of the best feature we added to our campervan conversion… until it stopped working… Unfortunately, Webasto / Espar are prone to carbon buildup if some parameters are not right. What is carbon buildup (also know as soot, coking, carbon debris)? It’s evil! It takes root in the burner insert and slowly accumulates under the form of hard black/grey ashes:

Webasto Combustion Chamber Carbon Buildup

Nasty Burner Insert

 

This hard carbon deposit clogs the stainless steel “sponge” found in the burner insert; the role of this sponge is to diffuse the fuel and mix it with air. The hard carbon also builds its way up just outside this sponge, messing up the air flow in the burner and speeding up the carbon debris accumulation.

Webasto New Combustion Chamber

Webasto New Burner Insert. Notice the stainless steel “sponge” behind the holes (click the picture to zoom)





If the Webasto heater can’t start and/or shut down prematurely, it’s probably a symptom of hard carbon buildup. We had these symptoms after only 200 hours of using our Webasto Air Top 2000STC (we have the gasoline model).

Carbon buildup CANNOT be removed/cleaned from the burner insert! Because the stainless-steel sponge is so fine, it’s impossible to remove the carbon from there. An attempt to clean it will give the impression that it solved the issue, but carbon buildup will come back after a short period. This is what TechWebasto told us and we believe it’s true, because our burner insert was cleaned and the symptoms came back after about 75-100 hours…

Well, cleaning the burner insert didn’t work. It looks like we have to replace the burner insert and this is the topic of this article! But first, we would like to eliminate the source of the issue… what causes hard carbon formation in the first place?? We’re no expert, but here is the information we gathered during our saga:

  • Webasto Gasoline models are more prone to carbon buildup than Diesel models! This is counter-intuitive, but this is what we were told by TechWebasto (quote: “because gasoline is less energy-dense than diesel“) AND we found SO MANY people with issues that we believe it’s true.
  •  A rich fuel/air ratio (too much fuel) will lead to carbon buildup. There is less oxygen at higher elevation, so the mix get too rich in fuel. If used frequently at more than 5000 feet, the unit should be adjusted for high-altitude usage (faroutride.com/webasto-espar-high-altitudes/). In fact, we will go ahead and say that the gasoline models should be adjusted for high altitude out-of-the-box, whatever the altitude you will be using the heater.
  • Air flow restriction in the intake/exhaust pipe. The total length of the intake + exhaust pipe should be less than 5 meters. If using an silencer, the length is reduced to 2 meters! Condensation accumulation in the exhaust pipe will also create air flow restriction, so a 3/16” drain hole MUST be drilled at each low point in the exhaust routing (see our Installation Article).
  • Short cycle time. If the Webasto is fired-up, it should be run for no less than 20-30 minutes.

 

Now that we have a better understanding of the carbon buildup causes, here is our plan:

  • Replace the burner insert with a new one (keep reading for more!)
  • Perform the following to reduce the chance of carbon buildup:
    1. Remove the exhaust silencer.
    2. Drill drain holes at low points of the exhaust routing.
    3. Adjust the Webasto heater for high-altitude usage (we would do this even we didn’t plan on going to high altitudes). This is still O.K. to use it at sea level; the downside is that we can lose around 3-4% BTU, but we rather live with it than have carbon buildup again!

Are we sure these will solve the carbon buildup problem? NO! But we like our heater so much (when it works) that we’re willing to give it a try!

 

Material

We ordered these from a Webasto dealer (Webasto Dealer Locator):

  • A new burner insert (Part Number 84883A, 130$. It’s the same for the ST and the STC model. This part number is for the GASOLINE/PETROL model only)
  • A new set of gasket (don’t attempt to re-use the same gasket!)
Webasto How to Install New Combustion Chamber - Material

New Combustion Chamber (burner insert) and New Gaskets




Resource

 

Let’s do this!

First things first, get that faulty Webasto heater out of the van. Since we installed it ourselves, we figured how to remove it: http://faroutride.com/air-heater-installation/

Webasto How to Install New Combustion Chamber - Removal

Get yourself comfortable!

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We want to thank our friends Chuck and Sam for hosting at their place during that process, that helped A LOT!! Sam is a young talented photographer about to build and move into a van, make sure to check him out!!

//

 

We now remove the plastic outer casing. No tools needed, it’s all clipped-on:

Webasto-How-to-Install-New-Combustion-Chamber-Outer-Casing

 

We then use a flat head screwdriver to spread the retaining clip of the fan:

Webasto-How-to-Install-New-Combustion-Chamber-Fan-Removal

 

Next, we disconnect all the connectors from the control module:

Webasto-How-to-Install-New-Combustion-Chamber-Disconnect-Connectors





And we remove the control module. There are 3 screws to remove:

Webasto How to Install New Combustion Chamber-7

 

The control module can then be removed:

Webasto How to Install New Combustion Chamber-8

 

Next, we remove the combustion fan module. There are 5 screws to remove:

Webasto How to Install New Combustion Chamber-Combustion Fan Screws

 

The combustion fan module can now be removed. Discard the gasket:

Webasto How to Install New Combustion Chamber-10

 

We’re getting close to the burner insert. Remove these 4 screws and the 3 rubber grommets:

Webasto How to Install New Combustion Chamber-Burner Insert Screws

 

Now, pay attention. The complete combustion chamber assembly wants to come off, but it won’t work because the fuel pipe (which is attached to the burner insert) won’t clear the cutout. You need to separate the burner insert from the rest of the combustion chamber assembly. They are slightly sticked together, use a little bit of force or use a flat head screwdriver to pry them apart. Here is a picture showing how they come apart (the picture was shot later in the process):

Webasto How to Install New Combustion Chamber-9

 

Note that there is a gasket between the burner insert and the combustion chamber, discard it.

 

Here is the removed burner insert:

Webasto How to Install New Combustion Chamber-Burner Insert Removed

 

There is definitely carbon buildup in there:

Webasto How to Install New Combustion Chamber-Carbon Buildup

 

The flame monitor (gasoline models only!) and the glow pin are still attached to the old burner insert. Remove them and keep them for re-installation in the new burner insert:

Webasto How to Install New Combustion Chamber-Glow Pin

 

Here is a sneak peek inside:

Webasto How to Install New Combustion Chamber-Cast Block

There is soot in the form of fine black powder. We cleaned it using a toothbrush and White Gas (Camp Fuel). (the manual says to use benzine, but we’re not sure where to find that?!):

Webasto How to Install New Combustion Chamber-Combustion Chamber Cleaned

 

O.K., it’s time to re-assemble everything using the new burner insert and the new gaskets. Just do everything in the opposite order! Be very careful not to bend the fuel pipe of the new burner insert and be careful to replace the electrical wire at the exact same place they were. Just look at the pictures above as reference.

 

We’re done with the burner insert replacement!

 

Next, we adjusted our heater for high-altitude usage to prevent (hopefully) carbon buildup issues in the future. Here is an article we wrote to perform that task:

Webasto / Espar: High Altitudes Usage

 

 

We then started the heater and it fired-up like a new! Nice!

That’s it for now, but make sure to check “ON SECOND THOUGHT” below:

 

 

 

ON SECOND THOUGHT

Was all this effort worth it? We still don’t know!! We performed this by October 14th 2017, time will tell if it solved our issues or not.

Update will be posted here:

No update yet, wait for it…

 

 

Cheers!

 

You might be interested in these articles:

Webasto Air Heater Installation

 

 

 

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ABOUT US

Hello! We’re Isabelle and Antoine, a couple dreaming of being on the move and we’re seeking for the ride of our life. We bought a Ford Transit van, converted it to a campervan, sold our house and hit the road full-time to make our dream a reality. We are sharing this in hope of inspiring and helping others to follow their dreams too!

 

 

CHEERS!

 

 

3 comments

  1. Comment by John Gassel

    John Gassel Reply November 7, 2017 at 8:00 am

    Hey guys, I know it hasn’t been that long since you made these changes but I’m wondering if you have a quick update? I’m about to pull the trigger on a heater (after doing tons of research) and we’re very curious how the Webasto is treating you now.

    Finding an appropriately sized gas heater is tough. Espar doesn’t have a good solution imo, since the B4 is too big and the B1LC seems outdated. I like the idea of gas over propane for a few reasons. I recently heard that the STC model will replace the ST (even in the US) so I might go that route anyways. It is a lot cheaper. Given the price and the thorough guide you’ve posted I’m really leaning to doing this install as well (with your lessons learned).

    Thanks so much!

    • Comment by Antoine

      Antoine Reply November 7, 2017 at 9:10 am

      Hey John,
      It’s only been about 40-60 hours running time since we “fixed” the Webasto, so we cannot draw any conclusion. So far so good (it’s still starts and runs well), but time will tell.

      If issues come back, we will probably install a DIESEL Air-Top with an diesel aux. tank. The diesel models are less finicky, so I’ve heard. I don’t like the idea of having to fill a separate diesel tank, but there are not many other options…

      Let me know what is your final conclusion!!

      • Comment by John Gassel

        John Gassel Reply November 7, 2017 at 10:16 am

        Hey Antoine, thanks for the quick repsonse! I’ve definitely considered going with a Espar D2 and a separate tank. I suppose the Webasto diesel is another alternative. I’ll let you know what we decide to do.

        Cheers, John

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