Webasto Advice Needed ....

[Ray Davis]

Kathy and I are parked at Bob and Debi's farm in Landum SC. We are backed down towards their horse barn, dry camping.

Last night it got down to around 40 degrees, so at 1AM I turned on the webasto heat. I heard that familiar roar of the burner igniting (Woohoo, I thought).

Then, about a minute later I hear the sound of something like boiling water, and a series of clunks or bangs underneath the bedroom area. Then the webasto shut itself down.

Marathon assured me that the webasto was tested during their PDI, but I didn't re-test. After the PDI they did a 50,000 mile service, which I believe included changing engine coolant.

I am wondering if a valve got turned off in that process or ???

I haven't located any manuals specific to the plumbing, so I'm asking the collective POG brain trust.

Any ideas where to start looking? The unit seems to be working pretty much OK. It starts, but I think the overtemp is shutting the unit down, because perhaps the coolant is not being circulated. I haven't yet been outside, but I do believe I heard the circulation pump.

Anyway, thoughts would be appreciated. I am going to be dry camping for 4 days at West Point next weekend, and I'm thinking it's going to get cold.

Thanks,
Ray

[Joe Cannarozzi]

I think you are on the right track you just have not yet found that closed valve.

[truk4u]

Ray,

They probably turned off the valves to the heat exchangers closing the loop. I don't have a clue where your valves are, on my 97, one was down under the fan drive gear assembly forward of the bottom belt bellows and the other was in the starboard engine door near the chassis batteries.

[BrianE]

Ray, As a general rule, make sure all of the valves in the engine compartment are turn on. You may have had a transient overheat caused by air in the system. There is a purge valve that is probably in the drivers air compartment behind the grille next to the driver that has a shrader valve on top of it. It will be in the top of the compartment as it is the high point in the system. Try running the drivers heat pump while holding the shrader valve open with a screwdriver tip. Have a rag handy while doing this. Then suggest you station yourself at the unit while Kathy cycles it on. If you hear anything you don't like, tell her to turn it off again. You might have to go through this process a couple of times if there is air in the lines.

Someone else might be able to chip in on how to run the Webasto pump without starting the burner but I think running the engine and or the driver's heat pump will accomplish the same thing.

[Kevin Erion]

It sounds like air in the system to me as well. On my 99 there was a valve behind the large panel in the front ahead on the passenger seat. This valve looks like a small water valve used for a ice maker water line. It should have a short plastic line that you can put into a small bucket or whatever to catch the coolant. Brian explained whats next, good luck an call me if you have any questions on my cell.

[Jon Wehrenberg]

Rather than chasing a Schrader valve to purge the system (which may not have the air bubble at it) I have learned from changing my coolant three times now on the current coach with a Webasto to make sure all valves are open.

Bring the engine up to operating temperature so the thermostat is open because the thermostat does inhibit system flow, and set the temps at the thermostats as high as possible and turn on the Webasto. I can't speak about Marathon specifically, but that method circulates coolant through every part of the system. On my coach it is the best method to "burp" the system.

The engine absolutely has to be into the normal operating range.

The burner should not fire at all once the system is above about 160 degrees.

[Ray Davis]

Thanks for the help everyone. I tried Jon's method, i.e. starting coach, and then getting up to temp and running all the thermostats. Seems to have cleared it up!

Woohoo! POG comes through again.

Thanks everyone for the help.

Ray

[lewpopp]

Happy you've got the heat system working because Kathy said earlier today that it was going to 25 at home tomorrow and it's about the same latitude as West Point.

[adamdegraff]

Thanks for the help everyone. I tried Jon's method, i.e. starting coach, and then getting up to temp and running all the thermostats. Seems to have cleared it up!

Woohoo! POG comes through again.

Thanks everyone for the help.

Ray

Ray,
did it turn out that you had a valve closed? I having the EXACT same problem you described. I did just have the bus in for service. Nothing done to the wabasto though. I'm wondering if they might have closed a valve inadvertently or something. With my block heat button pushed, I'm getting heat in the living area. But turn off the block heat button and I get a short burn from Webasto, then a few clunks under the bed, then burn shuts down and I hear what sounds to be a straining sound from the pump?

Thanks,
Adam

[aggies09]

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.

[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

[hhoppe]

Ray: If you did have an air bubble in the system, it was probably caused by the coolant service. The coolant drains out easier than it reaches all parts of your systems during re-fill.. Please check your coolant level in your coolant tank. After my coach purged it's air bubble after water service I had to add three gallond of coolant. Glad to hear your under way.
Jon: I liked your sustem of water service. Thanks.

[Ray Davis]

Hi Harry,

In my particular case it was not an air bubble, but the return solenoid which is normally open (bypassing the engine), wasn't open. This meant there was no open path for coolant to move through the system, and the coolant boiled in about 60 seconds, causing a thermal shutdown.

I had first thought it was a an air bubble in the line from a coolant change, but determined if I hit the dash switch to pre-heat the engine (which swapped the two solenoids), then the heater would run, i.e. the path was open.

Removing the valve guts is a simpler solution, and was suggested by Marathon.

Ray

[hhoppe]

Good remedy Ray. Thanks for the follow up, now we all have that avenue to follow. Glad your on the road again. That cold weather has got to be tough on a SoCal boy. Safe Journey's

[Ray Davis]

We'll see you out at Havasu!!

Ray