Webasto

[adamdegraff]

Might be having a problem with my webasto... and it's getting cold.

Enabled the webasto and turned up the thermostats. Fans at vents are blowing. Air is cold. Webasto is NOT firing. Sound at webasto is a bit high pitched... strained.

So to see if it will fire, I hit block heat. (Do all coaches have webasto set up to heat block?) Now it fires up, and well at that. No smoke, just a clean, hot burn. Water temp rises quickly. AND, the living room starts heating up. Ahhh, as I understand it, with the block heat button pushed, it opens up a circuit that allows the heat from the engine to be used to heat the living areas... and domestic hot water as well.

Turned block heat off. Living areas got cold again. Turned on webasto to heat domestic water, fires right up. But this time, it doesn't heat the living area. Only when the block heat button is pushed.

Is it possible that the valve that allows the webasto to heat the living areas is stuck shut? And then the "heat" only gets to the living areas when the block heat circuit is open?

About to go to Montana. Do I need a part? Yikes, it's going to be cold up there.

Thanks for any advice. It's late and cold:-)

Adam

[adamdegraff]

Well, since I'm the only one up at 1:55 Pacific time, I'm gunna just keep talking to myself here until you early risers check in.

I just read Ray's post from yesterday. Same EXACT problem. I too just had a service done at Marathon, Coburg. I did have my coolant filter changed, though I did not need my coolant changed. Do we think the Al might have turned a valve off and not turned it back on? He did forget to turn my fuel back on after changing the fuel filter. That was an easy one to diagnose though. (He was quite embarrassed.)

Well, for now, I have the block heat button pushed and am sitting in Pendleton, OR, nice and warm even hough it is 45 and very windy outside. Webasto is firing nicely. And, as I understand it, is circulating hot coolant through my engine, domestic hot water tanks, and living area. (As, with the block heat button pushed, all systems are opne? Is that correct?) So, go ahead, sleep in. We're plenty warm for now. But if anybody knows what's going on, after you have a nice big breakfast, drink you coffee, and read the paper, please, drop me a hint for the quick fix.

Thanks,

Adam

[rickdesilva]

Adam
I have had the same problem, my fix was to remove the cover and take a hammer and lightly "tap" the individual valves for each zone. Apparently if you don't use the unit frequently the valves get lazy and don't open up. I worked for me a few times, hopefully this is your problem also.

[truk4u]

Adam,

Assuming your valves are open (1 in the starboard engine compartment and 1 down under the radiator fan assembly) you may have a pump or solenoid problem. Here's how my 97 Marathon worked:

12v Heat Button - Webasto fired and circulated coolant to the house heat exchangers. Pumps never shut off while 12v heat is selected and continue to run. Webasto cycles on and off based on temperature of the coolant. Thermostats control the fans for each heat exchanger.

Engine Heat - This button on the dash fires the Webasto and circulates coolant to the engine only, controlled by pumps and solenoids.

Block Heater - 110v block heater controlled from the electrical cabinet with a circuit breaker. It's either on or off and has to be manually plugged in at the engine compartment.

12v Water Heater - Webasto fired and pumps and solenoids controlled the coolant to the hot water heaters. You also have 110v heaters for water.

The Marathon system is different than the CC I had and my current Liberty. I am assuming your 95 chassis is set up the same as my 96 chassis, but there could be differences.

It sounds like a solenoid problem. Mine did not heat the engine with the 12v house heat selected, but maybe they made a change. If your stuck, call Leon in Oregon at Marathon and he can steer you in the right direction.

[Jon Wehrenberg]

When I got my coach I made a schematic drawing of my Webasto system for future reference. It takes a little time to visually follow the routing of coolant lines and the associated valves, but having done that it makes an understanding of the system fairly easy.

[MangoMike]

Adam,

There's also a Webasto primer over at Prevoman.com

http://www.prevoman.com/Pages/Webasto/Webapage1.html

Picture 12.jpg

Mike

[Joe Cannarozzi]

I have a webasto that fires up correctly the 2 circulating pumps come on the blower starts and the burner fires up.

It comes up to temp and first the burner turns off and after 5 min. the blower shuts down. Circulating pumps continue to run.

Here is where the problem arises. The blower and burner never even try to come back on the circulating pumps continue to run till the lines go cold

If I shut it down for long enough I can start it back up and it will repeat the symptoms.


Batterys are good and fuel filters clean.

[ajhaig]

Joe,

We had a problem like that with our Webasto, it turned out that the section of the exhaust pipe inside the Webasto box had a small crack and the heat from the exhaust gasses that built up inside the box shut down the Webasto unit.

I hope all is well in the Windy City, I'm keeping busy with the kids (the "storm"), my Farmall - and dreaming about our next Prevost!

AJ

[Ray Davis]

Another possibility is that the light sensor inside the burner unit is dirty. There is a small unit, looks almost like a mirror, with two wires coming to it. It's job is to "see" the burner burning (it's light sensitive). If it doesn't see the fire burning, it shuts down around the 1 minute mark. Generally wiping it clean will help.

Ray

[Joe Cannarozzi]

Well after taking a good look at the manual and a couple of calls to wabosto techs we have decided it is the control thermostat.

You guys are making me work I thought I could rely on POG for that kind of info, Sheeeeeesh.

It is mounted right on top on the heat exchanger end under a small plastic cover along with and overheat sensor and some other small electrical device.

It's the size of the last joint of my thumb 90 bucks. Ordered a spare tip too.

We will see.

I opened it up and it all looks good. Previous owner had paperwork for recent service new tip and filter.

The guy was from Arizona the only time he probably used it was to periodically run it on tests and the problem does not show up till a good long while.

It was 30 last night and from dead cold until it got up to temp and the burner went off it probably took 45 min. and that was with the blowers in the cabin running. Is that about right. Seems like you start getting heat in the cabin very quickly.

Our bus has a e-spar and it needs to go. Wabesto is way easier to get to and open up. The folks on the phone are also speaking English not German