Webasto may have lost prime, tips?

[dbsoundman]

My webasto was working great in early October, but of course now that it’s really cold, it doesn’t want to fire up. The pump comes on, and I can see the system draw a little more power at times when I think it might be trying to ignite, but I don’t hear any clicks and there sure isn’t any heat being generated.

I know I need a new fuel filter but I imagine I have already, or will, lose prime. What’s the best way to prime these things? I am not experienced in this kind of stuff but I’m willing to figure it out.

[cadillackid]

what kind of webasto is it? the little one or the big long cylindrical type? (scholastic 45 / DB2010)?


the smnaller ones ignite with a glowplug and the clickety clack dosing pump.. the big ones are essentially like a Home Fuel-oil Boiler.. each has a completely different ignition cycle and sequence..

[dbsoundman]

Originally Posted by cadillackid

what kind of webasto is it? the little one or the big long cylindrical type? (scholastic 45 / DB2010)?


the smnaller ones ignite with a glowplug and the clickety clack dosing pump.. the big ones are essentially like a Home Fuel-oil Boiler.. each has a completely different ignition cycle and sequence..

I’m not sure yet, I’ll try to get the cover off today while there’s still some daylight and check it out.

[cadillackid]

I went through the ignition cycle of my big yellow DBW2010 heater..

first the water pump should come on, then the fan motor comes on (this is the combustion air fan.. which also drives the fuel pump mechanically).. then the fuel solenoid opens and the sparker starts sparking and you get ignition..


the Most common failure on these units is the bearings or foreign material in the fan.. this causes the 'A' fuse to blow. and you wont hear the fan motor sound. the fuses are inside what looks like a capped-off 6 pin electrical connector. the bearings get stiff from sitting and the motor wont spin.. you can change the fuse once and tr yagain if its popped.. if it doesnt start then you need to disassemble the heater..


the second most common failure is the motor itself burns up.. and thats the kiss of death.. new motors are hard to find and they cost $500+ a piece..



I have a webasto DBW2010 unit with a burnt up motor currently.. it costs me less including shipping to order a brand new unit from china of the same style... I have one on the way to tear into pieces and examine.. if the motors match whats in my real webasto I may order a bunch of motors and offer them as replacements for the DBW2010 / Scholastic 45 motor replacements as an alternative..

[dbsoundman]

well I know the fan comes on because I can hear it and I feel cold air coming off the exhaust pipe outside…sure hope it’s not the motor!

[cadillackid]

Originally Posted by dbsoundman

well I know the fan comes on because I can hear it and I feel cold air coming off the exhaust pipe outside…sure hope it’s not the motor!

thats a good sign! cold air from the exhaust pipe is in fact the fan.

[dbsoundman]

It's a DBW2010! I'm not sure they ever took the cover off this thing either, it was like opening an ancient Egyptian sarcophagus...


Fuel filter is definitely crusty so I'm still thinking that's the issue. I saw there's one relay in there that had a little corrosion on the terminals but I pulled the connector off and the blades were clean so I don't think that's the issue. I attempted to fire it up with the cover off, and I heard the fan going, pump running, and I heard a little clicking noise that almost sounded like a relay not quite staying on...not sure if that's the fuel solenoid or if that's an indication of the problem?


FWIW it sounds like the water pump and the fan come on basically simultaneously in my unit.

[cadillackid]

yep thats exactly like the one in my garage..



the fuel pump drives off the front of the same shaft the fan runs on.. the multi-clicking you hear is the Spark ignitor .. its mechanically gear driven by plastic gears which love to break.



the fan and water pump start up simulateneously on power-up.. the sparker starts pretty shortly after.

I have the repair manual for these but i cant put it on the forum, the PDF is too big..



the yellow can is your heat exchanger and fire chamber.. all the magic happens in the other end of the unit.. it is hinged so theoretically you can swing the right-side end open to work on it, adjust / replace the nozzle etc..



im assuming the fuel tank in your bus is full enough that the heater dip tube is down in the fuel? ive seen some of these "factory" installed with the dip tube way up (like just below halfway down)..



the fuel solenoid is inside the burner head (the black and gray part on the right in your pics.. ).. there is an overheat sensor in series with it.. that sensor is a non-resettable one-time-blow type device.. it will go off if the heater was ever fired with no water in it..

[dbsoundman]

Originally Posted by cadillackid

yep thats exactly like the one in my garage..



the fuel pump drives off the front of the same shaft the fan runs on.. the multi-clicking you hear is the Spark ignitor .. its mechanically gear driven by plastic gears which love to break.

I'm not hearing any clicking at this point, just the fan and pump. I hear them slow down a bit when I think it's trying to ignite (higher current draw off the battery), but it tries that 3 or 4 times then stops. The whole thing only runs for about 2-3 minutes then it auto shuts off.

the fan and water pump start up simulateneously on power-up.. the sparker starts pretty shortly after.

I have the repair manual for these but i cant put it on the forum, the PDF is too big..

I have a manual for these but I'll PM you to get an emailed copy of that PDF!

the yellow can is your heat exchanger and fire chamber.. all the magic happens in the other end of the unit.. it is hinged so theoretically you can swing the right-side end open to work on it, adjust / replace the nozzle etc..



im assuming the fuel tank in your bus is full enough that the heater dip tube is down in the fuel? ive seen some of these "factory" installed with the dip tube way up (like just below halfway down)..

I changed the fuel filter today and there was fuel in the old filter, tank is about 2/3 full so I think there should be plenty for the Webasto to run. Pretty sure when it ran before I had about a half tank...

the fuel solenoid is inside the burner head (the black and gray part on the right in your pics.. ).. there is an overheat sensor in series with it.. that sensor is a non-resettable one-time-blow type device.. it will go off if the heater was ever fired with no water in it..

I opened it up today (took me ever to get that stupid cotter pin out!) and didn't see anything obviously wrong inside the burner head, but I also wasn't really sure what I was looking at. I forgot to reread this post and look for that overheat sensor but even then I don't think I would have been able to find it. I cleaned the contacts on the two relays, that didn't make any difference, and I am almost positive that both the water pump and the blower are running when I turn it on, I felt both of them while it was on and it seemed like they were going, plus I know there was coolant moving around because I could hear it gurgling a bit inside the bus.


Do you have any other bright ideas? I took a video of it running if that would help to explain what it's currently doing. I did have the radiator flushed earlier this year and I'm not sure the mechanic knew I had a webasto so they may not have purged the air from it, but the webasto also ran fine several times after the flush, without any signs of being "unhappy". Really the only difference is now the temperatures outside are sub-40 rather than 50s to 70s like the last time it worked...

[cadillackid]

when you look at the burner side of that swivel.. the nozzle is in the center.. it unscrews and will have a number stamped on it.. the 2 pointy wires right above it are electrodes.. there is a transformer behind them similar to an automotive ignition coil.. so those electrodes are supposed to Arc a spark between them. .they are generally somewhat close to the nozzle so they are near the oversrpay from the nozzle..



those electrodes often get carboned up and you'll have no spark.. you would notice quite a bit of fuel or wetness in and around the nozzle and the burn chamber if the fuel solenoid is turning on and pump works.


you could unplug the fuel solenoid and run the heater.. you should see sparks at the sparker and have 12 volts going into the coil (hump on the top with 2 wires going in.. you can see more if you take the black plastic cover off)..



you can test fuel flow by unplugging the ignitor wires and running it.. you would get a fine mist of fuel.. (be careful you might want to catch it close with a rag and let it run only a few seconds.. its a .35 nozzle so it will pump .35 Gallons per hour at 100 PSI...



on mine I can Hear the sparker.. sounds like a some faint 'Zzzzzzzzz'



if it were mine id pro0bably clean the electrodes and the nozle (or replace the Nozzle.. ) the numbers stamped on it tell tyou what it is so another can be ordered..



it should be a 0.35 with a 60 degree spray for that heater..

[dbsoundman]

Originally Posted by cadillackid

when you look at the burner side of that swivel.. the nozzle is in the center.. it unscrews and will have a number stamped on it.. the 2 pointy wires right above it are electrodes.. there is a transformer behind them similar to an automotive ignition coil.. so those electrodes are supposed to Arc a spark between them. .they are generally somewhat close to the nozzle so they are near the oversrpay from the nozzle..



those electrodes often get carboned up and you'll have no spark.. you would notice quite a bit of fuel or wetness in and around the nozzle and the burn chamber if the fuel solenoid is turning on and pump works.


you could unplug the fuel solenoid and run the heater.. you should see sparks at the sparker and have 12 volts going into the coil (hump on the top with 2 wires going in.. you can see more if you take the black plastic cover off)..



you can test fuel flow by unplugging the ignitor wires and running it.. you would get a fine mist of fuel.. (be careful you might want to catch it close with a rag and let it run only a few seconds.. its a .35 nozzle so it will pump .35 Gallons per hour at 100 PSI...



on mine I can Hear the sparker.. sounds like a some faint 'Zzzzzzzzz'



if it were mine id pro0bably clean the electrodes and the nozle (or replace the Nozzle.. ) the numbers stamped on it tell tyou what it is so another can be ordered..



it should be a 0.35 with a 60 degree spray for that heater..

Excellent info, thanks! I'm not sure when I'll get back down there to look, I just put the cover back on this afternoon as I'm hoping to take the bus out for a drive this weekend, but I'll definitely take a closer look at the electrodes once I locate them. I'm not hearing the sparker, I remember hearing it before, so I think that's the source of my problem. However when I opened it up it was also totally dry (at least from what I saw) so I'm not sure it's pumping in fuel either?

[cadillackid]

webasto doesnt have much diagnostics for these. . but the 3 fuses are a good start, cant remember if you checked those.. they are on what looks like a Capped-off 6 pin in-line electrical connector, on mine at the top of the bracket.. that connector opens up and there are 3 fuses in there..



the overheat sensor supposedly is 2 white wires.. maybe it can be jumped out? it should be closed.


the diagnostics they want you to do is via a controller tester.. webasto part number 5011070A



it apparently is a rather expensive device..

[dbsoundman]

Originally Posted by cadillackid

webasto doesnt have much diagnostics for these. . but the 3 fuses are a good start, cant remember if you checked those.. they are on what looks like a Capped-off 6 pin in-line electrical connector, on mine at the top of the bracket.. that connector opens up and there are 3 fuses in there..



the overheat sensor supposedly is 2 white wires.. maybe it can be jumped out? it should be closed.


the diagnostics they want you to do is via a controller tester.. webasto part number 5011070A



it apparently is a rather expensive device..

Yeah, I found the fuses, didn’t have my multimeter on me but they all looked clean and intact.

There was a thing in the back, looked like a red plastic bottle cap, it may have had two wires going to it? I’ll take a closer look next time.

[cadillackid]

Originally Posted by dbsoundman

Yeah, I found the fuses, didn’t have my multimeter on me but they all looked clean and intact.

There was a thing in the back, looked like a red plastic bottle cap, it may have had two wires going to it? I’ll take a closer look next time.

thats the inertia sensor.. if you wreck the bus it shuts the heater down.. that rubber cap is a resttable pushbutton, it should be set.. so nexct time you are at the heater, press that button.. I was thinking its wired to the mains so nothing would run at all if it was tripped.. cant hurt to press down on the top of it and see if it clicks in.