Webasto Dual top 100 removal and repair.

[merl]

Just got back from our five day east coast heatwave escaping excursion during which we discovered the webasto heating/water unit won't fire up, the unit throws a 'failed ignition' fault, while it was trying to ignite I noticed and smelled black smoke coming from the exhaust.
Took a look on the internet last night and frightened myself with the cost of replacement and or spare parts so today I've decided to try and remove the thing (it's underslung at the rear of our Tribute PVC), take it to bits and see what's occurring.
Any input from anyone who's had similar issues and any guidance is most appreciated. Wish me luck

 

[merl]

Got the little sod off anyway.

Thinking about going on mastermind with a specialist subject of 5hit fasteners.
Amul Ragen;
Q, "Why do manufacturers of stainless hose clamps still use a plain steel nut and bolt"?
Me;
A, Erm...."To make sure something goes rusty so it makes future jobs really difficult"?
Amul Ragen;
"Correct"

 

[mistericeman]

Stainless nuts on stainless bolts can be just as bad
And harder to cut off than mild steel...

Is that exhaust running uphill ?

They should usually have a fall to prevent build up of condensation from combustion gasses ..
Unless it's got a weep hole at the lowest point

 

[Drover]

Older ones had a reset button in the centre at the top.no idea on this new stuff.
Faulty fuel pump or a leak would be my first guess.but have have passed that.
Next glow plug or o ring fault.
There are loads of videos on internet on how to control the lump hammer you will end up clouting it with before buying a Chinese job to replace it with...

 

[merl]

Stainless nuts on stainless bolts can be just as bad
And harder to cut off than mild steel...

Is that exhaust running uphill ?

They should usually have a fall to prevent build up of condensation from combustion gasses ..
Unless it's got a weep hole at the lowest point

Pretty sure it was, thanks.

Older ones had a reset button in the centre at the top.no idea on this new stuff.
Faulty fuel pump or a leak would be my first guess.but have have passed that.
Next glow plug or o ring fault.
There are loads of videos on internet on how to control the lump hammer you will end up clouting it with before buying a Chinese job to replace it with...

I can only find one video of my actual webasto unit and that's a nice company video and everything is spotlessly clean and comes apart dead easy .
It hasn't been too bad TBF. Looks like a build up of crud and soot in and around the burner.
Going to give it a damn good clean up and if that doesn't work then it'll be a damn good thrashing Basil Faulty style.

 

[mistericeman]

Takes a surprisingly small amount of carbon build up to stop the fuel vapourising correctly and the glow pin to fail to ignite it (usually with associated coughing and white smoke)

The carbon is usually the result of the additives in modern fuels....

It's why kerosene/parrafin/jetA

Results in a usually spotless burn chamber.

 

[merl]

So gave everything a good clean up with brushes and an airline, now I'm covered in crap.

 

[merl]

Gauze and glowplug was by far the worst area, scraped the thick off then soaked it in petrol for an hour then a gentle scrub with a stout brush and then blasted a whole can of brake cleaner through the gauze in the right direction via the fuel line. Took quite some time before the cleaner ran clear so hopefully the gauze is clean enough to last a few more years?

 

[merl]

Is that exhaust running uphill ?

They should usually have a fall to prevent build up of condensation from combustion gasses ..
Unless it's got a weep hole at the lowest point

Yes, it's running uphill and you're correct, according to the installation instructions the exhaust should fall continually to prevent condensate being trapped. There's not a lot I can do about it because the exhaust exits the heater at the very bottom and is already very low and the lowest thing on the van (apart from the tires!). I'm wondering that maybe because the exhaust, which is quite long, actually falls all the way back to where the hot exhaust leaves the heater that it's impossible for condensate to gather at that point because its simply too hot and gets boiled away? I dunno but it's been like that for 12 years and doesn't seem to have caused an issue so Im inclined to leave it alone, not sure I want to start making a hole in it??
The instructions also say the exhaust has been terminated on the wrong side of the van too, should be on the offside opposite the hab door which makes sense, I'll probably move that over because it would be far less smelly on the opposite side to the woosh bang and the awning, if we use the privacy room sides the exhaust is currently actually INSIDE the 'tent'! Not Good