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.