Webasto Question (I think)

[MangoMike]

Gordon,

I've worked on both and as Jon and others have said the plumbing is quite different between the two. I do not have a diagram for the Marathon.

JDUB and I have both had failures w/ the ignition coil so I would start there.
Mine looked fine until I removed the 4 screws on the top and removed it from the head. Looking at the bottom I found it all melted. A couple of ways to check it: 1) remove the head and remove the wire to the fuel pump, the connector just pulls off, and have someone hit the switch to start the unit. You should see a spark across the electrodes. You want to pull the fuel wire so that fuel is not spurting all over the place. If no spark then it's either the coil or possibly the brain. I would then remove the coil from the head and remove the two leads (grnd is the brown one). Then I would add power directly to these two leads to see if you get spark. You need to check as some systems are 12v and some are 24v. If you now get spark then I would check the power to the brain and hope that's not the problem. Not cheap.

Paul,

If your valves are open correctly I think Dale has identified the problem, since there was just a coolant change it does sound like a bleed is in order.

[GDeen]

Ray,

I can't hear anything from mine. I did not go stand next to it while someone else fired it, just tried to start several times and all I got was cool air blowing from the registers. We were heading out to the park and I quit fooling with it. After reading the posts here about the noise from the firing though I am quite sure I never got that far. The window were open and I heard nothing standing next to the bedroom SMX controller as I tried to get it going. Went down and checked the unit a couple of times to see if I could tell if it was burning while the fans were blowing, but all quiet in the Webasto bay.

I also read your post about the solenoids a couple of days ago as well as Flyyou Guys posts about his problems. Would love to have a schematic to chase all the valves down so will create one as I go.

Mike,

Thanks for the direction. I will work that angle and hope it isn't the brain.

[phorner]

Last night, I let the Webasto run all night to see if it heated the hot water tank. That answer this morning was no. However, the Webasto DID heat the inside heaters, so I now knew for sure it was a plumbing issue, which is what I had suspected all along.

Following Jon's suggestions, I looked for the valves in the water heater bay for the hot water jacket.... and sure enough, although I hadn't seen them before.... there were 2 gate valves that were clearly marked Water Heater Heat In and Water Heater Heat Out. And they were closed.

Opened these valves, turned the Webasto back on, and in 20 minutes had VERY hot water.

I now have every reason to believe that running the engine now will also produce hot water, as it has in the past.

Thanks, Jon, and everyone else for their responses and suggestions.

Is this a great forum or what!

We're in Hammond, LA and on our way to OKC.... but we're takin' the long way.

[merle&louise]

Paul,

If you and Janice have time swing down thru Houma and stop and visit with us. There is a great place to park close to our house: full hook ups (50 amp) and the best food in south Louisiana across the street.

We hope you can make it.

[phorner]

Tuga,

Thanks so much for the invitation!

Unfortunately, we're headed out early tomorrow for commitments further west.

Wish we could have made it. Sure sounds great!

[Ray Davis]

Gordon,

I'll mail you a PDF file of my webasto plumbing. It's too big to post on the forum, unfortunately. Yours should be very similar.

Ray

[Will Garner]

Ray,

If you can get the file directly to Skiffer perhaps he can place it in the Articles section on the home page. That way anyone can access it for reference material.

Hope to see you and Kathy at OKC come October. Carole and I are really looking forward to the rally.

[Ray Davis]

This particular file is specific to my coach (I got it from Autocad drawings from Marathon). I'll re-draw it in a format that we can post, and upload it.

It details the webasto plumbing, but like the other coaches mentioned, I get hot water from driving, which indicates there must be a coolant path through the water heaters in addition to the webasto path. That isn't (unfortunately) detailed on this drawing.

For those that have a Marathon, (assuming similar to mine), there are two solenoid controlled valves in the webasto bay (left side front of engine bay). The valves are on the right-hand side of the bay, just to the right of the webasto unit.

One is normally closed, and one is normally open. In the regular configuration, coolant is supposed to be heated, run through the heater and/or water heaters, return through the normally open valve to the webasto.

When the "block heat" button is pressed on the dash the two valves reverse, and coolant returning from heaters/water-heater travels through the engine, and then returns back through the normally closed valve. This allows you to heat the engine with the webasto.

IN my particular issue, my normally open valve was clogged/broken, and there was no path for the coolant to return to the webasto, so the unit would boil-over in about 30 seconds, and shut down due to the thermal sensor (accompanied by loud banging noises!)

At Marathon's suggestion, I just removed the guts of the valves, and now, the coolant always flows through the engine, and via the direct path. It might in very cold weather take a bit longer to heat the coach, but I don't have to worry about those darn valves.

There was another post here about a year ago about someone who rebuilt those valves and manifold, which I might do in the future, when nothing else needs fixing on the bus!

Ray

[phorner]

In the Webasto bay on our coach there are 4 valves in question. Two are quarter-turn ball valves marked "Auto Heat" supply and return and two are gate valves marked "House Heat" supply and return.

Does anyone have a good explanation as to the meaningful difference between the them?

My Liberty manual says that the Auto Heat valves should be closed during hot weather when the OTR air is being used. Any comments about this?

An lastly, if all 4 valves are closed, does this completely close the Webasto plumbing loop?

[Ray Davis]

Paul, it sounds like you may be similar to the Marathon (I'm not sure). We too have 4 valves, but two are solenoid controlled rather than manual.

One set of valves send the Webasto coolant through the house heaters, and routes back directly to the webasto without the engine.

When we hit a "block heat" button the dash, two of the valves reverse (which I assume is now in your auto-heat mode), and the webasto coolant is now run back through the engine, rather than direct from the heaters. IF your thermostats are not calling for heat, then the path to-through the heaters inside is closed, and the only path would be through the engine at that point.

IN your case I am guessing they might be two separate circuits. The house heat valves send coolant inside to your heaters. The auto-heat sends coolant around through your engine. The purpose of that would be to heat your engine when it's really cold outside using the webasto, before firing up your engine.

The issue I had with my webasto system is that the normally open return valve for the house-heat wasn't working, and the coolant had no path to circulate, and it caused the coolant to boil in about 60 seconds, and shutdown shortly afterwards.

And yes, I would venture to say that if you close all 4 valves, there is no webasto flow in any direction. I would make sure you do not fire it up when all closed, as that will cause the boiling issue that I experienced.

Ray