Author Topic: Webasto system maintenance related information  (Read 560 times)

John Fitzgerald

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Webasto system maintenance related information
« on: January 24, 2022, 05:20:32 PM »
I am going to perform maintenance on my 1995 Marquis Webasto heating system and would like to know if anyone has information on the system.  I have the Webasto manual that came with the coach, and it really just covers the boiler itself, and I could not find any information in it other that how it runs in a common truck/tractor install.  Does anyone have a Beaver specific wiring and piping diagram?  I have looked through all of the online diagrams on this site and can't find one that seems to be for my coach.  My plan is to flush and replace the coolant, and it seems to be shared with the engine.  Also I want to pull out the heat exchangers and clean out the 27 years of junk collected on the fans and coils.  If anyone has done this please let me know.  BTW, after buying this coach last May (my first real motorhome) I have really learned so much about all the system in these beasts.

Thanks

John Fitzgerald
1995 Beaver Marquis Garnet
300 Cummins 8.3
1995 Jeep Wrangler Rio Grande

Eric Maclean

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Re: Webasto system maintenance related information
« Reply #1 on: January 24, 2022, 05:47:58 PM »
John
What model Aquahot do you have?
Coach assist library has a link to the Aquahot manuals under heating.
I believe in that vintage coach you have a model
 AHE 100- 411 which is very close to the AHE 100- 02S although yours will likely only have one circulation pump as opposed to one for each zone.
The boiler has a copper loop inside that the engine coolant runs through the Aquahot does not share the coolant with the engine
And can be drained without draining engine .
The domestic hot water loop is an external loop  of copper tubing rapped around the outside of the boiler and encased in heat transfer compound this eliminates any chance of cross contamination with boiler fluid allowing you to run regular automotive antifreeze .
It is important to know that the domestic hot water loop can not be effectively blown out with compressed air to winterize and must be winterized using plumbing antifreeze.

Hope this helps
Eric
« Last Edit: January 24, 2022, 06:06:52 PM by Eric Maclean »
1997 Patriot Yorktown
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2009 Chevy HHR
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Demco Air Force one tow brake.

David T. Richelderfer

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Re: Webasto system maintenance related information
« Reply #2 on: January 24, 2022, 06:29:13 PM »
Eric -

Webasto Company, a German company, is located in Stockdorf, Bayern, Germany, and has a USA office located in Michigan.  Aqua-hot Corporation, a USA company, is located in Longmont, CO.  After a little research, it appears they are nearly separate heating devices - the Webasto versus Aqua-hot, and it appears the companies are not related.  Although... I know the Aqua-hot control device, a small rectangular box, is called a Webasto and is likely originated from the Webasto Company in Germany.

Our coach has the AHE-100-02S Aqua-hot and it does have a common coolant loop going from the coach engine through the Aqua-hot and forward to the dash heat.  Our coach can be heated by the Aqua-hot diesel burner and/or the Aqua-hot 120v electrical heating element and/or heat from the running coach engine.  I presume engine coolant is pushed through that loop by the coach engine's water pump.  In addition, the Aqua-hot has an engine pre-heat function with a water pump in the Aqua-hot for pushing heated coolant between the Aqua-hot, engine, and dash.

I believe the Webasto RV heating device and the Aqua-hot are two different animals.  Someone more knowledgeable needs to chime in to educate us.

2004 Beaver Marquis Sapphire

John Fitzgerald

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Re: Webasto system maintenance related information
« Reply #3 on: January 24, 2022, 09:57:14 PM »
Mine is definitely not an Aqua Hot, if there isn't anyone here that has a similar vintage coach I will try my best to document the system.  I am an industrial HVAC tech, so this type of system not in a coach is familiar to me.  My system is working, but one of the fan units is really loud, I think is is clogged up with debris.  I want to find out how the thermostats are wired to the main boiler, and how the fan units are controlled.  I found two relays under the sink that I think are for the front and rear zones.
« Last Edit: January 24, 2022, 10:04:41 PM by John Fitzgerald »
Thanks

John Fitzgerald
1995 Beaver Marquis Garnet
300 Cummins 8.3
1995 Jeep Wrangler Rio Grande

Eric Maclean

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Re: Webasto system maintenance related information
« Reply #4 on: January 24, 2022, 10:19:11 PM »
David
I may be wrong but I though John was working on an Aquahot unit

You are correct that Wabasto and Aquahot are two different company's how ever Aquahot used  a Wabasto diesel burner and combustion chamber from the Wabasto DBW2010 model to build their Aquahot units they don't build there own diesel burner.
When I rebuilt my AHE 100-411  the combustion chamber was cracked and leaking coolant into the combustion chamber
When I cut the chamber out of the tank I discovered that Aquahot had taken a regular Wabasto DBW2010 and cut the water jacket off  the combustion chamber and welded the chamber into their 1/4 steel end plate to create their boiler tank I also noticed while I was inside the tank that the coolant tubes which run to and front engine and heater core where a cooler poop of 3/4 copper tubing any that the engine coolant doesn't mix with the Aquahot coolant.
Aqua hot uses their own thermostat design but still uses Wabasto control electronics to operate the burner
As time went on Aquahot developed more complex control systems but continued to use the Wabasto burner.
If you compare your AHE 100-02S burner with the Wabasto burner you'll find there identical.
Here is a link to the Wabasto DBW 2010 for comparison.

https://www.suremarineservice.com/Heat/Hydronic-Heaters/DBW2010SW-12.html?gclid=Cj0KCQiAubmPBhCyARIsAJWNpiN22bcpVuEhqe8g6Oz-Yvq1q7dcIl4G4U7Pwb4XUGwCaaFDE54Lh-0aAvlvEALw_wcB

Hope this helps
Eric


1997 Patriot Yorktown
3126-B
2009 Chevy HHR
Roadmaster falcon tow bar
Demco Air Force one tow brake.

Eric Maclean

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Re: Webasto system maintenance related information
« Reply #5 on: January 24, 2022, 10:22:29 PM »
John
Sorry for the confusion
So it is a true Wabasto unit .
Do you know the model ?
It appears that Beaver used the Aquahot from 1996 on I was not aware they used the Wabasto unit before that .
Their are wiring diagrams for the 1996 Aquahot relay board in coach assist but I can't find anything on the earlier systems with the Wabasto .
Your heat exchangers are likely the cozy heat exchangers and the plumbing would be dependant on the number of heating zones and circulation pumps Beaver used.
I would assume the are relays to operate the zones and the number of wall thermostats should give you an idea of the number of zones.
As to the component location maybe someone else with the same vintage coach could help out.
I'll keep looking to see what I can find

It's not uncommon for things to get stuck in the heat exchanger fans , dust dirt wire ties  pencils etc which will make noise or even stop the fans.
Good luck

Eric
« Last Edit: January 24, 2022, 10:42:00 PM by Eric Maclean »
1997 Patriot Yorktown
3126-B
2009 Chevy HHR
Roadmaster falcon tow bar
Demco Air Force one tow brake.

John Fitzgerald

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Re: Webasto system maintenance related information
« Reply #6 on: January 25, 2022, 11:29:37 AM »
I am busy until late in the week, but will get the model information and trace out the lines.  I know there is a field built manifold of sorts on the forward engine compartment bulkhead with an isolation valve there.  Unless there is a separate heat exchanger somewhere to isolate the engine coolant from the heating loop fluid I assume they engine coolant is what flows through the Webasto.
Thanks

John Fitzgerald
1995 Beaver Marquis Garnet
300 Cummins 8.3
1995 Jeep Wrangler Rio Grande

Fred Brooks

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Re: Webasto system maintenance related information
« Reply #7 on: January 25, 2022, 01:44:20 PM »
   John,
To the best that I can remember, there were some units that just had the "stand alone" Wabasto Diesel furnace units like installed in "over the road" trucks. I recall that Country Coach did this around the same period as Aqua Hot was being considered. Regardless the main thing that you have to do is clean the nozzle and combustion chamber, replace the diesel fuel filter that should be close by, and take some compressed air and blow out the heat exchangers. The original application on over the road trucks was tied into the cab heater core and coolant loop so they did not have to run their engines all night long. Let us know how it turns out. Fred
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John Fitzgerald

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Re: Webasto system maintenance related information
« Reply #8 on: January 25, 2022, 02:28:02 PM »
Thanks Fred, we are on the same page.  I am finding that my coach is unique, as most Marquis were 'customized' by the original purchasers option choices.  I am the kind of person that when I work on something that I own, and don't fully understand it will take the whole thing apart, then put it back together the 'correct' way.  I am a big fan of making things as the manufacturer designed, assuming they knew what they were doing.  So it appears I have a truck heater, that heats the engine (or gets heat from the engine) and two zones in the coach.  I have not pulled apart one of the fan coil units yet to see how they are set up.  I assume they have an internal aquastat to run the fan when hot water is present at the coil.
Thanks

John Fitzgerald
1995 Beaver Marquis Garnet
300 Cummins 8.3
1995 Jeep Wrangler Rio Grande
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Eric Maclean

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Re: Webasto system maintenance related information
« Reply #9 on: January 25, 2022, 04:16:42 PM »
John
You are right about the differences in coaches .
I am again your coach has three or four heat exchangers which are usually floor mounted spread out around the coach the most common exchanger used was the cozy brand I've included a link to let you see what they look like.

https://heatmyrv.com/product/cozy-3-heat-exchanger-exe-103-0ex/

I don't think they ever had internal thermal switches though
The zone control was usually accomplished by a wall mounted thermostat which also ran the roof mounted A/C unit if so there is usually a switch on the thermostat to switch between A/C and heat if you have two A/C units it is likely you have two heat zones

Hope this helps
Eric.
1997 Patriot Yorktown
3126-B
2009 Chevy HHR
Roadmaster falcon tow bar
Demco Air Force one tow brake.
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