Our Van’s Webasto Heater Stopped Working in High Altitude.. Troubleshooting & Solution!!

**Update: It's been 3 weeks since we fixed our heater in this video and it's been working with no issues. One thing we avoided doing was turning it on when in really high altitude (7000'+) to avoid it to stop working again. We've been in ~5000' to 7000'.**
This is the troubleshooting and solution for our Webasto heater that stopped working in high altitude (~9200’ in elevation). Our Webasto is an STC Air Top 2000 (Gasoline Version) purchased from Heatso (UK).
Here’s our back story. My heater’s been working with no issue since Dec of 2020 (a little more than 1 year), and it’s been primarily used in the North East. We just started traveling to higher elevation recently: we were traveling from New Mexico (we were in Taos Ski Valley for 1 day - I believe thats ~9000’ in elevation - and had no issue.) We got to Colorado last night. We were camping at the Zapata Falls BLM campground (~9200’), and thats when it stopped working. I noticed the carbon pieces on the ground in the morning, and that’s when this video starts.
*Disclaimer: I am not an expert in this manner, nor do I claim to be. This is just what I did to try to troubleshoot this issue. Please use this information at your own risk.*
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Here’s my notes for the troubleshooting & solution (for my situation). The 3 fault codes I was getting were F01, F02, and F08 (I did not pay attention to the fault codes until later in the troubleshooting process). This is my interpretation of the error codes for our high altitude situation.
1. F01: So much carbon buildup that the heater won’t even start a flame:
Solution: Use the blower directly into the intake tube to blow out an carbon buildup (while the heater is turned off)
2. F02: This codes happened after the heaters been working for a while, but then stops working (due to carbon buildup)
Solution: With the heater running, use the blower to blow out all the smoke and carbon buildup to “flush” the heater. I was blowing it intermittently until no smoke was coming out of the exhaust. The blower also helps push more air into the burner to help the flame stay burning in our lower oxygen environment.
(It was actually quite satisfying to see the black soot and puff of black smoke come flying out of the exhaust lol.)
3. F08: Based on the fault code manual above, its “Combustion air fan blocked” or “Combustion air fan short circuit”. It’s possible that when I was using the blower to blow out carbon buildup, it got stuck or blocked the fans from function properly?
Solution: Run the lockout reset sequence several times (here: www.manualslib.com/manual/119.... Usually for a different error code lockout, doing the lockout reset sequence once will fix it. However I had to use the lockout reset sequence multiple times (like 10 times) before the error went away. Not sure why.
*Bottomline: Pay attention to the error code and look out for smoke coming out of the exhaust: If there’s smoke (black or white), there’s probably carbon buildup inside the heater - follow above solutions to blow it out*
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Now that it’s been fixed, I am actually not sure if I am still in “high altitude” mode because I had to run the lockout reset sequence so many times. I am getting mixed information that resetting the power to the heater does not revert the “high altitude” setting back to it’s original state, but some people saying it does. I am skeptical that it may have switched back because the fuel pumping “clicks”, they sound pretty fast still (similar to the pace prior to running “high altitude” mode sequence). But there’s no way to test it without proper equipment. Anyhow, the “high altitude” mode sequence was ran.
Hope this is helpful for someone!
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Resources:
- Setting it to “high altitude” mode faroutride.com/air-heater-ins... and www.stokeloafvan.com/blog-1/w...
- Idea to remove muffler from exhaust faroutride.com/air-heater-ins...
- Where I got the idea blowing out the carbon buildup • Webasto Gas Heater FAI... / • Video
- Video interview with Webasto techs to learn more about the gasoline model and “high altitude” mode • Vanlife Outfitters Web...
- How to reset lockout www.manualslib.com/manual/119...
- Fault code output and details (Page 506) www.butlertechnik.com/downloa...
- Elevation checking whataltitude.com

[@albertomendez5213]

thank for share this information. i just fix my problem thank to you. By chance of life I had exactly the mattress pump just like yours. I'll take the heater out later and clean it better later. 👍🏽 great tip.

[@RinaandMichael]

Glad it was helpful!!

[@SPQR-Z]

The fix is don’t run the heater at elevations higher then Webasto recommends. That unit needs to be removed, disassembled and totally cleaned out. I saw a YT video where someone used a air compressor and blew it out by spraying air directly into the ports on the heater itself. That should work as a temporary fix but eventually it needs to be properly cleaned. I’ve used these Webasto and Espar heaters for many years and they are really quite fuel efficient, reliable, low electrical draw and have many advantages for RV use. They do require more maintenance then a propane furnace because they don’t burn as cleanly. At least every other season you take them apart and clean out or replace the burn chamber and sensors. The muffler/exhaust pipe, air intake should be inspected for insect nest or debris blockage. The actual maintenance only takes a couple hours at most but getting the unit out depends on access IE: how buried it is in your van. As long as you adhere to the altitude restrictions then you shouldn’t be experiencing any problems that regular maintenance should prevent. I’m buying my 4th unit for my newest van build a Webasto Duel Top air/water diesel heater. It’s altitude limit is 7200 ft so pretty high. Honestly most people camp below 5k ft most of the time so should not have these kind of problems. Glad to see you get it up and running so you wouldn’t freeze and thanks for the mattress pump tip. Never would have thought of that hack

[@callmebackfriday2]

Thanks for sharing the information. This really helps.

[@RinaandMichael]

Glad it was helpful!

[@oneadVANtureatatime]

Thank you for taking the time to share this information. We are having a similar problem and are planning to do a rebuild soon due to carbon build-up. We used ours at high altitude for two winters so I guess we are due.

[@RinaandMichael]

You’re welcome! Was any of this information helpful for your situation?

[@oneadVANtureatatime]

It was helpful to see the bits of carbon coming out the exhaust. That's exactly what ours looks like. Now that I have seen you try some of the quicker solutions I know I will need to go for the full burner replacement and gasket kit. I have been dreading this as it will probably take me about 5 hours to do. 😂

[@RinaandMichael]

Nice, good luck with the replacement!

[@TeutonicNordwind]

Hey there. New sub here. Saw your update comment in the info. So what is your alternative/solution if you are staying in 7000+ alts? Or are you avoiding overnights, etc?

[@RinaandMichael]

Thanks for the sub! Since then we havent really stayed too many times above 7k’ using the heater. Anytime we are in high altitude now, we make sure to turn the heater on full every time we run it. We removed the air intake filter to maximize oxygen flow. The exhaust muffler is also removed. I think adding 85-86 octane gasoline might’ve help to reduce the richness of the gasoline going to the heater (i added 89 when i had this issue). Doing all this we haven’t ran into the same issue since. Hope this helps!

[@yellowmistery911]

Just happened to us in colorado haha and we end up at Walmart

[@cjam3660]

interesting, a gasoline geater issues with carbon build up ? . yea iv been sold on going with A gasoline wabosto, but not now, shouldn't be effected with Carbon build up nor should altitude really effect it. . I just see too many issues with all these type heaters eventueally...im not paying over a grand for a headache eventueally. I'm finding a heat score 100% full proof...ill keep looking. thank you, best wish

[@RinaandMichael]

When not in high altitude this heat has worked flawlessly. I like the fact that theres no need for another type fuel source. Theres pros and cons!

[@jackkirkpatrick2388]

Do Not buy This Unit! used it two nights at 8-9000 feet. It Now Does not work. It's almost brand new. Cost me nearly $2000. Completely unacceptable that Webasto does not allow for it to be leaned out for altitude. Crappy engineering. The guys where I bought it said it would be okay for occasional use at this elevation; IT IS NOT. So if you want to use it at this type of altitude application you have to go through this mess of cleaning it out every other time you use it... or go down to sea level. JUNK!