Webasto Heater No Fire

mc5a Jon · October 31, 2009, 12:26:45 PM

I need to know how to diagnosis the webasto unit on my bus. It has no markings I can see for model#. Its very dirty, smells like fuel, has broken exhaust pipe right out of the unit. The coolant flows though it but it never fires up. I really don't have any idea how to go about fixing it! It was most likely installed in the mid 80's. Should I remove it and just start tearing into it or is there anything I can try with it installed. Also where can I find an engine oil heater for an 8V71? The old girl doesn't start under about 40.

bobofthenorth · October 31, 2009, 03:56:53 PM

Can't help you with the Webasto but the simplest way for a temporary warm up on a cold pan is a mag mount block heater like this. You can also buy pencil heaters that mount in the pan but then you've got to pull the pan and weld in the mount or find something that fits an existing bung. Unless its on a daily driver that probably isn't worthwhile. Everyone who lives in an occasionally cold climate should have at least one mag mount block heater lying on a shelf somewhere.

belfert · October 31, 2009, 04:00:45 PM

The Webasto, when working, may also preheat the engine depending on how installed.

Sorry I can't help more.

plyonsMC9 · October 31, 2009, 04:25:32 PM

Greetings Jon & welcome to the BBS!

Can you post a picture or two to the group to help identify the unit?

Thanks !

Phil

edroelle · October 31, 2009, 05:10:52 PM

The Webasto manual has diagnastic procedures. Also, the technical assistance if very good 1-800-555-4518.

This is a copy of the service manual for the 2010 coolant heater.
http://www.suremarine.com/manuals/webasto-repair-manuals/dbw2010-2020-300-repair.pdf

Ed Roelle

luvrbus · October 31, 2009, 05:12:36 PM

Jon, www.suremarine.com has trouble shooting guides and manuals on their website for Webasto units hope it helps but most of the time it is no power or ground to the unit

good luck

Gary '79 5C · October 31, 2009, 05:15:02 PM

Jon,

I would head to the Webasto site and check for the op's manual for the 2010 unit, (I think that is the unit most popular)
I would check for a rated/nominal voltage, not sure if it is a 24V of a 12V.
After that Check that you are getting proper input voltage.
Are you getting fuel flow, I think the blower is a single shaft to the fuel pump, so check both for rotation.
Not sure if there is a flow switch in the coolant line thru the "boiler". No flow, no fire, sometimes.
Next are you getting ignition ? Again voltage dependant.

These are some basics, but It got me up & running. My biggest problem was a poorly routed 12V supply cable was internally high resistance ground between POS & NEG, repaired that all ok, Finding that was tough...

Good Luck,

Gary

buswarrior · October 31, 2009, 06:30:48 PM

Take the business end off and see what it looks like.

Go through the trouble shooting procedures in the manual. One of the safety fuses may have blown, due to it being poorly maintained. I'd save the more complicated checks until you confirm all the safety circuits and electrics are right.

What is the interior of the combustion chamber look like? soot? oily? Clean it out.

Same as an oil furnace, a fresh nozzle and confirm the sparker is good, and you'll be off to the races.

Get your nozzle from an HVAC guy, not Webasto...$$$$ saved.

If you are a hard core tool guy, there is a test box available to plug in in place of the control box that lets you cycle all the bits.

Don't go applying test power to the wrong places, the control box is a $500 item...

happy coaching!
buswarrior

happy coaching!
buswarrior

Nick Badame Refrig/ACC · October 31, 2009, 09:05:28 PM

Hi Jon,

If your circulator is running, chances are that you may have either tripped the limit at the top of your combustion

chamber, or you have a stuck blower in the burner, or a broken fuel line.

I would need further info of what the start sequence you are hearing or not to provide you with a solution.

Feel free to call me on monday
609-263-2296

Nick-

Sam 4106 · October 31, 2009, 11:54:23 PM

Hi MC5A Jon,
The 2010 Webasto burner in the Aquahot on the MC 8 we bought in June had a similar problem, especially the fuel smell and not burning. I took the burner unit off the combustion chamber, disconnected the fuel feed line, hooked up my garden sprayer (with fuel in it) to the fuel inlet line, pumped up the pressure in the garden sprayer, and found a fuel leak at the fuel pump back plate (opposite the input shaft). I removed the back plate plate and found a leaking O-ring. I went to a local hydraulics repair shop to get a new O-ring and found that neither a standard nor metric O-ring match. I then went to a business that repairs Aquahot units and learned that that O-ring isn't available as a separate part. They wanted to sell me a new fuel pump for $384 and change. Since the previous owner had left a new complete burner unit in the bus I put that on instead. When I fired up the new burner heavy white smoke came out of the exhaust pipe for at least ten minutes. I guess it took that long to burn out all the excess fuel in the combustion chamber. I have only tried the burner once since the initial run and it burned clean. That may not be what is causing your problem, just relaying my experience. Good luck finding your problem.
It really burns my tail pipe that Aquahot won't sell a $.50 O-ring to repair a fuel leak in the pump instead of wanting to sell a complete pump. I would still like to repair the pump so I could have a spare working burner. Nick, any chance of getting an O-ring from you? It is between the back plate and the pump body and is not shown in any of the parts diagrams or lists I have looked at on the Webasto or Sure Marine websites, nor the owners manuals for either the Aquahot or the Webasto that I have. Any help would be appreciated.
Thanks, Sam 4106/MC8

Nick Badame Refrig/ACC · November 01, 2009, 06:22:54 PM

Quote from: Sam 4106 on October 31, 2009, 11:54:23 PM
Hi MC5A Jon,
The 2010 Webasto burner in the Aquahot on the MC 8 we bought in June had a similar problem, especially the fuel smell and not burning. I took the burner unit off the combustion chamber, disconnected the fuel feed line, hooked up my garden sprayer (with fuel in it) to the fuel inlet line, pumped up the pressure in the garden sprayer, and found a fuel leak at the fuel pump back plate (opposite the input shaft). I removed the back plate plate and found a leaking O-ring. I went to a local hydraulics repair shop to get a new O-ring and found that neither a standard nor metric O-ring match. I then went to a business that repairs Aquahot units and learned that that O-ring isn't available as a separate part. They wanted to sell me a new fuel pump for $384 and change. Since the previous owner had left a new complete burner unit in the bus I put that on instead. When I fired up the new burner heavy white smoke came out of the exhaust pipe for at least ten minutes. I guess it took that long to burn out all the excess fuel in the combustion chamber. I have only tried the burner once since the initial run and it burned clean. That may not be what is causing your problem, just relaying my experience. Good luck finding your problem.
It really burns my tail pipe that Aquahot won't sell a $.50 O-ring to repair a fuel leak in the pump instead of wanting to sell a complete pump. I would still like to repair the pump so I could have a spare working burner. Nick, any chance of getting an O-ring from you? It is between the back plate and the pump body and is not shown in any of the parts diagrams or lists I have looked at on the Webasto or Sure Marine websites, nor the owners manuals for either the Aquahot or the Webasto that I have. Any help would be appreciated.
Thanks, Sam 4106/MC8

Hi Sam,

I found those O rings in a cheap O ring set sold at Harbour Freight. The set has about 100 different O rings in it.
Even if the ring is not exact, it just needs to seal the fuel from leaking.

Good Luck
Nick-

stegey · November 01, 2009, 07:04:20 PM

Hi if its made by Webasto then you should find the manual ( install – service & repair – parts ) you need here .... http://www.techwebasto.com/thermosystems_main.htm .
Try the Recreation Vehicle link or if it's out of production try the Archived Product link
Mike

luvrbus · November 01, 2009, 07:31:24 PM

Stegey, you can buy the o-ring from Rocket Seal in Denver CO

1-800-445-7803

www.rocketseals.com

They have a minimum order price but I forgot was it was, they have any o-ring ever made in different materails

good luck

Sam 4106 · November 02, 2009, 07:10:22 PM

Hi guys,
Thanks for the suggestions on a source for an o-ring.
Stegegy, I have looked extensively on several web sites and in the manuals I have and have not found a part listing for the O-ring I need. If you have a specific site and page showing it listed please refere me to it. Thanks
Luvrbus, Thanks for the Rocket Seal referral. I will call them tomorrow.
Nick, I will look for set on Harbor Freight's web site. There isn't a store in our area. I have tried several other stores in the area without success.
Thanks all for the help, Sam 4106/MC 8

gumpy · November 03, 2009, 05:26:40 AM

Quote from: bobofthenorth on October 31, 2009, 03:56:53 PM
Can't help you with the Webasto but the simplest way for a temporary warm up on a cold pan is a mag mount block heater like this. Y

Don't waste your money on that magnetic heater. I put one on my bus and it lasted about 2 months till it corroded and shorted out. Big sparks. Thought it was going to burn down the bus!

Buy an engine block heater element and install it in the side of the block. Simple and effective.