Webasto install 4905

[bryanhes]

I have read thru the many posts about installation for Webasto but would like some feedback from anyone with a 4905 and 8V-71.
1) Where on the bus did you mount the unit?
2) Where did you plumb it into the engine (Webasto info I found only goes back to 8V-92)?
3) Was fuel line hooked into the main fuel tank somewhere? And how was it plumbed?
4) In thinking about installing this early on in my conversion I would like to plumb it directly into factory coolant lines to heat the interior as well as pre-heat engine?

Thanks,
Bryan
1970 4905

[ruthi]

Hey Brian, my hubby installed this in our 4905. If you want info in it, you can call him at four seven 8 four 56 three three 5 six. His name is Ken.

[bryanhes]

Thanks Ruthi

[buswarrior]

In my MC8, the Webasto is plumbed inline in the big pipes heading forward to the heater cores. Mounted in the middle compartment by the previous owner.

It is a bigger DBW300 unit, so there is no issue with water flow when it is turned off and the engine is pumping the coolant for the defroster/heater core, it's pipes are the same size.

You need to be careful in your plumbing that the Webasto does not provide some sort of shortcut to unintended coolant flow. A solenoid valve may be advantageous, depending on what else you are plumbing, if the Webasto is parallel to anything else.

For those who have cut off the coach HVAC, the unused lines are a great place to plumb it. Same flow as when it was working, so Webasto hot output goes into the return line.

I'll think hard about an engine room install when/if I get around to liberating the space in my second bay.

The Webasto takes very little fuel compared to the Detroit. If mounted in the engine room, I'd tee off the filters, tee into the return, add an outboard engine priming bulb and shut off valves in both lines at the unit for servicing. Leave lots of line and space to get the business end open/off for regular preventive maintenance.

If the unit is to be further forward in the coach, add a pick-up and lines into one of the unused fuel tank access plates. Size it for future dual use with your diesel generator.

I like to live dangerously, my pick ups go right to the bottom of the tank.

happy coaching!
buswarrior

[Jerry Liebler]

Brian,
   I have a Webasto system, that I installed in my PD4107.  There are certainly differences between the 4905 and 4107 the similarities are very many and I'm sure that there wouldn't be much difference.  In a 4905 you'd have to choose the Webasto and components that matched your house voltage which could be either 12 or 24.  In the 4107 the only choice is 12 volts. Give ma a call to discuss @ 6064239854
Regards
Jerry 4107 1120

[bryanhes]

This might seem like a strange assesment but in trying to keep it simple for the time being in case I use it over the winter. Can I not just plumb the coolant into the exhaust and intake side of the lines that feed the heater cores from the engine through the bus. I guess my thinking would be that I have two valves in the engine compartment that look to create a loop through the entire system (both with shut off valves for summer and winter use) to heat the bus in its factory form. When closed there is no flow to the heater cores and when open, well we know where it goes then! So if in use and a good pump or two would it not push it through the entire system warming the interior as well as engine pre-heat? I believe there is a coolant pump in the HVAC compartment on the left side of the bus that pushes the coolant thru the heater cores as well. Just thinking out loud here 

Thanks,
Bryan

[bryanhes]

I forgot to mention I have had the thought of keeping the factory air set up to use while running down the highway just because it works so well and plumbing the duct work together with a basement air unit when parked to keep from using the gen or battery power to run AC. I would think I could duct it in toe kick areas possibly. Not sure how well it would work and how long the factory air will last before needing repair and then I know parts availability would be slim to none and expensive I am guessing. In the case that I do remove the factory air I would think the compressor location at the rear of the bus would be a great spot for the Webasto. Any thoughts on that scenario?

Thanks,
Bryan

[buswarrior]

I know an install where the Webasto was plumbed parallel to the big heater core.

It was a horrible failure without a way to close off the shortcut through the Webasto, while running the engine, most of the coolant flowed through the Webasto instead of the heater core. And the coolant wouldn't flow through the engine when attempting block heating, more of it went through the heater core.

Needless to say, the end users were mad at the whole vehicle in cold weather.

You must be able to positively control the coolant flow, it won't go where you want it if you give it a choice.

For now, sounds like just plumbing it inline to one of the heater lines would work fine for you.

Be sure that your hose connections are ribbed or otherwise able to mechanically withstand being under pressure. A smooth connection will pull itself apart, maybe not not today, maybe not tomorrow, but it will eventually!

happy coaching!
buswarrior

[bryanhes]

My thought was to plumb it inline with shut off valves and a T to redirect the flow from the Webasto to the original path when running down the highway. Or maybe I can run the Webasto running down the highway as well for additional temp increase and interior heat. I have not run my bus in very cold weather yet so I do not know how well the bus heat works. I would think with an additional pump it would push it through the system sufficiently. What say the group?

Thanks,
Bryan

[NewbeeMC9]

I am not sure I follow your plans or your system, I just want to mention that if you parallel the webasto to the engine, don't isolate the expansion tank in webasto only operation.  Just a flow shut off will be all you need during operation.  You can add Isolation valves, just make sure you have the ones you want open during the time you run it.

Example Idea
parallel you will tee into the engine discharge and supply and connect the webasto between. and possibly valves on all three legs of tees .  leave all valves open on return tee unless you are removing something

If running engine  Engine supply open, Webasto Closed, Heater system open

If heating only     Engine supply Closed, Webasto open, Heater system open   

if pre-heating engine and   you don't have check valves and you are able to back flow through the engine

                        Engine supply open, Webasto open , Heater system Closed


would be a simple system if you just wanted to hook in bus systems.

if you can not back flow through engine then you can add another tee and check valve to do engine pre heat so it flow one way through system.  Also remember that you will need juice to run the fans