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Old 12-12-2016
Debugjaws Debugjaws is offline
Senior Member
Join Date: Jun 2016
Location: Newberg
Posts: 200
Default Latest On My Webasto Conversion

It's been a while since I've updated regarding my Webasto conversion. Here is the latest. BTW - I have a bunch more pics but am having a difficult time loading more than one. If someone could provide a tutorial I'd be happy to upload them all.

I pulled the Primus system about 8 weeks ago and sold the boilers and control units. I purchased the Webasto from Rick Shawver. Super nice unit with about 90 total hours on it. It came enclosed in a super nice case with a stainless steel cover, installed primary pump, fuse block and 9 pin connector to hook up to.

While I was at it I also decided to change out the air pump coolant hoses, air filter, and camera system. All except the camera system have been completed (although the units have been purchased and arrived). One note of interest, my air filter is a single stand alone unit that is not encased. My air filter indicator was showing red, which I thought a bit unusual since the rig only has 52K on it. However, I have a pic that shows the culprits. There was a nest of 5 small birds who had somehow made their way inside. You can see they are quite crisp.

It needs to be said that there is no way that I could have achieved this without the WOG, and predominantly the help of Mose Wahlstrom, Bill Anthony, Bob Johannsen, and Rick Shawver.

Webasto - as mentioned this was purchased from Rick Shawver. It came equipped with a Hella primary pump which I use as the pull pump. I purchased a second Hella pump off of eBay and use it as a push pump on the intake side of the system. I also purchased the male electrical connector that matched female connector and conducted all wiring through it.

Box - I had D&S Sheet Metal Design modify my existing Primus box to lower it 5 inches to allow for the Webasto case and cover. You can see the 5" extensions on all 4 walls in the pic below. While at it I borrowed Bob Johannsen's idea of a trap door. Super handy. I've already used it post installation to lower the unit to do some wiring debug work with Hank from Webasto.

Electrical - the Webasto requires a constant 12 volt line and a switched 12 volt line to operate. Through the connector there are also a number of grounds. As well there is a line that allows for a secondary pump, and a line for a light that is on while it is in operation.

Constant 12 volt was sourced fresh from the panel in the closet.
Switched 12 volt. I sourced this from the front Primus wiring. I ran this through a lighted toggle to a thermostat that I mounted mid coach, and then through the Bosch relay that controlled the front Primus. From there it goes to the switch line on the Webasto.

I also ran a line to a system light that I mounted to the new control panel that I fabricated up front.

Engine Pre-heat - my pump wasn't working. So while at all of this I ran a new 12 volt source from the upper electrical panel at the front of the coach to the existing switch. I also ran a control light to the new front control panel that lets me know when this is on (actually ... So I don't forget that it is on ... Age!). The engine pre-heat was super handy as I needed it this weekend to start the coach.

Plumbing - taking another clue from Bob Johannsen and others I built a manifold that allowed me to run the two supply lines into one as well as the two return lines into one. Each line is run through a valve that allows me to adjust flow. As well, I also ran valves at the Webasto on the input and output lines prior to the manifold. This allowed for priming of the Webasto, then the manifold lines separate from the Webasto, each side individually and finally the whole system together. All that was needed after that was to balance the output to the reservoirs.

I will be replacing the individual reservoirs with a stainless steel single reservoir tank that I also had made by D&S. Capacity is a little more than 2 gallons with high and low level sight glasses. It will replace the other tanks, will sit about 1 inch below the rear start box and next to the engine oil fill pump meter, and will eliminate any further reservoir balance or overflow issues.

Thanks again to everyone who has helped. This thing works awesome! Now on to the camera and monitor!
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Gerry Lefebvre
Newberg, Oregon
91 WB 40'
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