Webasto Advice Needed ....

[adamdegraff]

Adam,

I guess there were several us trying to get our Webasto to work with cooler weather approaching. I was having the same experience as Ray and you. I found that I had two valves that were closed. Mine were located on the port side rear service bay. Once I opened those valves I had HOT air. Try to locate and check your valves to make sure they are open. That was my experience.

Still having problems. It seems all of my valves are open, but I'm not sure I'm looking at all of them. I can't seem to figure why any would have gotten closed. I ran the engine and turned the webasto on. Still cold air. I'm going to try to burp it. It would make sense that there might be some air in the system. I just had the coach serviced at Marathon, Coburg, and Al did change the coolant filter. Guess I'll poke around a little more. How can I be sure all valves are open? Righty tighty, Lefty, opens it up, right?

Any other suggestions are certainly welcome. It is getting cold.

Thanks,

Adam

[hhoppe]

This is a dumb question but are you sure your webasto thermostats are set high enough to bring in heat.

[adamdegraff]

This is a dumb question but are you sure your webasto thermostats are set high enough to bring in heat.

Harry,
yes, thanks for asking though. No dumb questions here.

Just to update:

I ran the engine until hot, hit 12V heat (webasto) and cranked the thermostats up. I hear the exchanger fans start to run. I hear the webasto fire up, nice clean burn, but then it stops, presumably due to the fact that the engine heat is now heating the water. At this point, my registers are blowing cold air. If at any point I hit block heat, which is a webasto engine preheater, (not the block heat plug in in the engine compartment) then the registers quickly start to blow hot air.

I bled the petcock at the front register. No air came out, but coolant did. Nice steady stream.

At this point, I can only assume it is a stuck valve that is somehow bypassed when the block heat is on. So, which one is it? The cold one maybe? :-)

FYI, I hear the circulator pump working at the webasto. It sounds strained when it is calling for heat, but I'm not getting any. (Doesn't sound strained when block heat button is pushed. Again, maybe an indication that it is trying to pump, but with the closed valve, it can't pump anywhere and is just sitting there trying its hardest?

Is there a way to manually open these valves? If so, I suppose I could open it up and try it. If I get heat under conditions that I didn't before, I guess it means I have a stuck valve.

Thanks,

Adam

[adamdegraff]

Adam,

I guess there were several us trying to get our Webasto to work with cooler weather approaching. I was having the same experience as Ray and you. I found that I had two valves that were closed. Mine were located on the port side rear service bay. Once I opened those valves I had HOT air. Try to locate and check your valves to make sure they are open. That was my experience.

One other question...

assuming I do have closed valves... what do they look like? Standard gate valve? (like you would use to turn on a garden hose?) I see some of them. They all seem open, but I will recheck.

Thanks,

Adam

[rickdesilva]

Adam
I had the same problem. Take the cover off the unit and locate the check valves for each individual zone. They are fairly easy to identify, just follow the heating lines into the unit. Mine are brass and lined up next to each other. Check valve, If the line is cold on the outgoing side of the valve, the check valve is sticky and needs a little coaxing. Get a hammer and give it a light smack. It happened 2 times to me and both times that was the fix.

[gmcbuffalo]

Adam
Call Marathon and tell them your problems. Maybe they turned off the two gate valves that islolate the engine from the coach interior. Meaning that they only changed the coolant in the engine circuit. I have a 91 XL and it has two gate valve just in front of the radiator behind a rubber flap.
GregM

[Jon Wehrenberg]

Adam,

Questions specific to a particular converter are best answered by owners of the same type conversion, or better yet, the converter.

All our Webasto systems function in the same basic way, but what makes all but Marathon or marathon owners incapable of answering your question is the flow path and valving is likely unique to Marathon coaches.

I have been pushing for a future rally to have a large number of attendees so we can encourage converter specific seminars put on by the converter. Our Prevost chassis are all enough alike so we can help each other regardless of conversion.

[Ray Davis]

An update ....

I thought the unit was working, but I fooled myself. As long as the coach is running, the webasto would fire, and stay running.

But, I didn't realize that the next day when I tried to run it, the banging started again and the unit would turn off.

I'm going to try to bleed it today. I've done the trial of running with engine going twice, lot's of heat, but still fails when running alone.

I haven't had a chance to try to locate the bleed points as I've been really busy with the trip. Hopefully this afternoon after I arrive I'll bleed it. Fingers crossed for a good result.


Ray

[adamdegraff]

An update ....

I thought the unit was working, but I fooled myself. As long as the coach is running, the webasto would fire, and stay running.

But, I didn't realize that the next day when I tried to run it, the banging started again and the unit would turn off.

I'm going to try to bleed it today. I've done the trial of running with engine going twice, lot's of heat, but still fails when running alone.

I haven't had a chance to try to locate the bleed points as I've been really busy with the trip. Hopefully this afternoon after I arrive I'll bleed it. Fingers crossed for a good result.


Ray

Ray, we should stay in touch. I've been in touch with Marathon as well. Maybe, since it seems like we are having the exact same problem, we can trouble shoot this together. My cell number is 304-667-4501. Any chance you'll be in Anaconda Montana tomorrow? Just kidding.
~Adam

[Ray Davis]

Just to close out this thread .....

In another thread, Adam mentioned that at a recent service at Marathon Coburg, that they neutered his webasto valves, i.e. took the guts out of the two solenoid valves controlling return to the pump.

Leon at Marathon suggested the same solution to my problem awhile back, and this weekend I had the time to go out and try that. I removed the guts out of the two solenoid valves, and the webasto seems to work fine. I was a bit worried about leaking, as it was a bit of a pain to get the valve tops off, and I didn't have replacement gaskets.

But, everything seems to be good. Webasto fires up and continues to run, putting warm/hot air in via the inside heat exchangers. It might be a bit slower now that it's always going through the engine (at least I think it is), but it's much better than shutting down in 60 seconds with banging sounds.

At some point I may consider getting valve rebuild kits, but it's a messy job, and I'm not sure I want to do it again! Even with hose clamp pliers, lot's of wrags etc, I lost over 1 gallon of coolant in the process.


I guess I'll get a chance to test this puppy out at Lake Havasu next month!

Ray