Webasto Heater (Air Top EVO 3900)

dougxn

Well-known member
Joined
Feb 22, 2022
Messages
72
Fluid Motion Model
C-28
Vessel Name
Celtic Sun
MMSI Number
368274950
My boat is from 2015 R27.

Say friends, my heater is blowing diesel. It has been raining a load, so I ran it for about 30-45 minutes- no change. So, I pulled it out, seems like not much to fix on this unit. A new burner looks to be about 300$ with gaskets. But I saw a knockoff brand for < $100.
IMG_3738.JPG
In addition, on the exhaust side, there is a tee with a copper pipe coiled underneath it that heads down into the hull. I presume this is some sort of recycling the fuel that doesn't get burnt. But it is leaking, so I will need to resolve this issue.
IMG_3746.JPG
So, what to do? I am sure some of you have either replaced or fixed the Webasto . Any after thoughts?

Last thing, I am pretty fed up with the crappy controls that come with this unit - a blue tooth or led display would be grand - anyone fixed this part of the equation? Actually, not that I have written this, what would be best is to have it connect to the nmea 2000 network!

Anyway, Thanks - dn
 
Hi Doug,

For a start, I would definitely work to deal with the leak. That needs to be stopped.

You may be correct that the burner needs to be replaced but I thought I’d share my experience. I have had smoke like your photo (and even worse). In my case the unit eventually shut down with an error code. Knowing that we previously had issue with a fender blocking the air intake causing this issue, just continually restarted the unit until the smoke cleared out. It sometimes took at least a half a dozen restarts to get it to clear. Once the excess fuel is all burned up the unit has worked flawlessly for years.

FWIW,

Curt
 
Knowing that we previously had issue with a fender blocking the air intake causing this issue, just continually restarted the unit until the smoke cleared out. It sometimes took at least a half a dozen restarts to get it to clear. Once

FWIW,

Curt
I've also heard of fenders blocking the exhaust and melting! 😀
 
All good stuff. I am leaning towards buying an HLN diesel heater. I pulled the Webasto apart yesterday to have a look - bad (10 years of soot). I think it is fixable, but for 200$ more I can have a brand new heater with bluetooth and a led panel. The Webasto kit is $498.

Oh, here is a few pix of the internals ; IMG_3777.JPGIMG_3779.JPG
 
I think if you clean it out thoroughly, you’ll be fine. Mine looked almost exactly like that, except it only took about four years before it needed attention. I cleaned the burner and the igniter, put it back together, and it ran perfectly.

One thing that really helps is running the heater at full blast, then shutting it down. Constant low-and-slow operation with frequent cycling is what causes carbon buildup in the first place.

You mentioned possibly switching to an HLN diesel heater, I’m pretty sure they are Chinese made, I’d stick with the German made Webasto. You already have it apart, you’re familiar with it now, and you know how to fix it. When I pulled mine out, I was surprised by how simple the unit actually is. Plus, there’s a lot of experience on TugNuts if you need help. Buying a new heater just adds expense and a whole new set of potential problems, which can easily turn into another headache. I would think it could be hooked to Bluetooth too, have you explored that? These units go into a lot semi-trucks as well, perhaps they have some Bluetooth options.
 
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