Webasto BBW46 / Eberspacher B5W coolant plumbing

[RJES]

Hello,
Does anyone happen to have the plumbing circuit diagram for the Webasto BBW46 / DBW46 or Eberspacher B5W (or D5W) coolant heater, as factory fitted to late T25's (maybe Syncro only????)? The circuit I need has two non return valves and a solenoid valve in the coolant circuit, and the details I am after is the exact plumbing of the heater and these three valves, including the orientation of the non return valves.
After having my Syncro for years I decided that it's about time I put the exhaust back in the Webasto, and had a go at getting it working. The heater itself seems fine, but I must have ballsed up the orientation of the pipes and / or valve flow directions, as the heater seems to rapidly overheat due to a lack of coolant flow. It then cuts out until everything is cool. I have tried a few alterations to the circuit, and drawing it out, etc, but every new one seems to create a new problem - the operation od the valves, and whether the engine is running or not makes it very hard to get your head around what's going on.
The factory workshop manual I have only covers the auxilliary air heaters, as fitted to earlier models, and does not ention the water heaters at all.

Thanks,

[RJES]

I've sussed what's wrong myself (in thoery), by drawing the circuit in each possible condition. It looks like I have one of the non return valves in backwards, but it's too wet and dark outside to go and turn it around now. A job for tomorrow.....

I'll be keeping the diagrams I've just drawn. If you need them, PM me and I'll scan them iand mail them to you.

[RJES]

I did have one of the non return valves in backwards, and the coolant now seems to go where it should.
However, the next problem is that after running for a while the 8A fuse blew, and continued to blow when replaced. I eventually traced the cause to the combustion air fan, which seemed to be working intermittently, and sometimes drawing over 17A.
Taking it to pieces, the combustion air fan is a strange device. I've never seen a pump like it before. It looks more like a positive displacement pump, except it has no displacement. It's not a centrifugal fan, but has a similar rotor. The rotor is sealed against it's housing with thick grease, and this grease was full of dust (hardly surprising, as I don't think the intake tube includes a filter???), so it seemed reasonable to clean the dust out, re grease it, and see if the current consumption dropped. It seemed to, and worked again for a while, before blowing the fuse again. This time I could hear the motor slow and struggle as the fuse blew.
Anyounr have a new combustion air fan for sale?

[manxman]

Sounds like you have the same problem as I had, What I think happens is the foam sound deadening in the intake tube brakes down over time gets drawn in to the fan (that spins at very high speed) buggering the motor and turning the old foam in to a sticky goo you are mistaking as grease.

take the intake tube off give it a shake and see

you have cleaned this out only to refit the intake tube, drawing in more old foam and starting the problem again.

my motor was so badly dammaged that all the plates on the armature had moved out of line rendering it totally buggerd.

new combustion air fan available from webasto approx £300. (can get just the motor from bosh, slightly different part no now but still not cheap)


ebay.de is the answer just keep looking few a few weeks and one will come along, or contact cj at syncrospares

I replaced my fan left the tube off and it seems ok if a little noisy.
I've also bought a new style Webasto intake silencer of ebay.co.uk (concertina tube + black plastic muffler) It's not ment for the bbw 46, and I've not fitted it yet but i dont see why it won't work.

also bought a whole set up for spares!

[RJES]

Hello Manxman - thanks for the reply - that's just the info I needed, I think.
I feel stupid now. I could see that there were bits of what looked like foam on the fan. I just assumed it was from elsewhere - it never occurred to me to look inside the card inlet silencer tube thing. It makes a lot of sense that there is foam inside, as it must do the silencing and filtering. Between the fan and housing it looked exactly like grease, but I know old foam goes stick when it breaks down, so I'm sure it would turn into a thick liquid when stirred enough. It also explains why it started up and ran OK for a while, before blowing the fuse again.
My motor worked fine when the fan wasn't attached, and it's only blown one more fuse since I put it all back together. Previously it had blown about 5 while I was messing about with it. The motor armature looked OK too. Hopefully it still is. It'll all be coming to pieces again soon then...

Did you replace the foam in the tube with something else? I can get foam no problem, but I guess it has to have the right amount of open cells? A chopped up aftermarket foam induction filter would no doubt be the right stuff. Wonder if ther's any cheap ones on eBay?
Phoning the Eberspacher / Webasto dealer did cross my mind, but I ruled it out as it would no doubt be expensive (£300 for a fan!). Also, the air / fuel ratio is adjusted with a bypass screw on the fan, so no doubt they'd want to charge loads for installing and recalibrating it too.

I've been on eBay.de earlier, looking for combustion fans. There were non, but there was a new Eberspacher B5W finishing in a couple of hours, but I'm not sure how compatible the rest of my Webasto system though, as the glow plug / fuel inlet area is definitely different.

Thanks again for the info,

[manxman]

the foam in the inlet is just a foam lining on the concertina tube, I think its just there for silencing, not filtering. ie there is an unobstructed path for air down the tube.

air by pass screw is factory set and should not be adjusted according to what I've read (not sure whether the matched to the burner or not)


Mine is working with nothing on the fan intake at the moment, but I've bought something like this to replace the old one, I'll stick it on tomorrow to see how it goes.

http://cgi.ebay.co.uk/EBERSPACHER-WEBAS ... dZViewItem

try a search on ebay.de bbw 46, throws up loads of complete units in various states

[manxman]

look what i just found, just what you might need

http://cgi.ebay.de/Webasto-BBW-46-Brenn ... dZViewItem

[RJES]

Hello Manxman again,
As it's taken me 4 years to get around to having a look at the Webasto, I thought I'd better finish the job while it's all in my head, and the tools are strewn aroiund my camper, so I've just been out in the rain, with an inspection lamp and removed the combustion fan again . Nice!
I stripped it again. This time it had sucked a massive piece of foam in. The fan was almost full of it. I cleaned it out again (WD40 seems to remove the foam / gunge better then amy other solvents I tried), and put everything back together. I just tried it again with no filter / silencer, as you have by the sound of things, and it works perfectly!
I can see why they have air inlet silencers though - it's damn noisy without one!
I'll be interested to know how you get on with that filter for a differnet model. If it works I'll get one too.

I searched eBay worldwide earlier for every combination od BBW46 I could think of, and never found that fan. Strange. I'm glad I didn't now though.

Thanks for your help - much appreciated.

[manxman]

no problem happy to help, i'll get back to you tomorrow when i've fitted the inlet pipe and silencer.


just for future referance,
woldwide serch on will ebay only turn up stuff that the seller has said he will ship worldwide, so loads of things can be missed. You have to search in ebay.com, ebay.de etc and then ask the seller if hes happy to send you the item or have it sent to a friend, relative, or even someone on here's address.

in the past i've bought a nos outboard powerhead for my 1968 85hp outboard by doing this, from a guy who would not ship outside the U.S.A!

[RJES]

Thanks, I thought it must be operator error on eBay. I occasionally search eBay.de for VW T3, and eBay.com for Vanagon, as that usually finds loads of interesting stuff. I've never used the 'worldwide' option much. I don't think I'll bother again either!

[RJES]

Just a thought - if you have a split charge system with two batteries, is your Webasto running from the auxilliary battery? Mine isn't, yet it has a factory fitted split charge system, which seems odd. I think I'll rewire it. I want everything which you are likely to run with the engine off to run from the 2nd battery.

[manxman]

can't help on that one, only have one battery in my 16" Doka, The heater is limited to run for an hour max so shouldn't flatten the battery in that time.

E D I T,

the heater will run for only half an hour max.

[manxman]

It all went far to easy today which is worrying, but here is what i did, with pictures hopfully,

This is the new intake silencer, (it's actually a filter to) that are available on ebay, fitted directly to the combustion air fan, on my spare heater.

It is a tight fit, I helded it in the steam from a boiling kettle to soften it a bit and grunged it on, its going no were now!





this if the combustion air fan I bought of ebay to replace the origonal one that sucked up foam and broke, not sure why this one malfunctioned (no foam in it) perhaps it was broke when i got it (wires had been cut, not a good sign) it was still working ,however very noisy, went quieter when forced to one side so maybe it had had a knock and wasn't lined up, any way the armature had been grinding away at the magnets.



this is it all back together installed in the van, with the fan and exhaust silencer of the spares unit. fits a treat, I was a bit worried about heat transfer from the heater conducting through to the inlet silencer and melting it but the flow of air keeps it cool enough and on shut down the fan carries on a while to cool down the unit a bit so it seems to be ok.





And its as quiet as a church mouse now to


I'll keep an eye on it for a week and run it up a few times to road test it, but from how its gone today I'd recomend this mod to anyone with one of these heaters, and if you don't want to buy a new silencer just pull the old one off and bin it before your fan gets buggered to!!

[Ye Olde Syncrospares]

hi,ive a selection of these webasto heaters for spares if needed cheers cj.

[toomanytoys]

Might need one myself CJ and poss one of the solenoid cooant valaves as I think one is stuck open preventing the engine from warming very quickly... will have a look this weekend..