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Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: Jim Eh. on March 20, 2018, 01:49:40 PM

Title: Engine heater fuel supply point
Post by: Jim Eh. on March 20, 2018, 01:49:40 PM
Has anyone ever tapped into their generator fuel supply line to run their aquahot or diesel fired engine heater. My concern is cavitation occurring in the aquahot/engine heater when the generator is running. I think the run time that they may be both running would be low but from time to time they would both  be running at the same time.
Also if the generator only is running would it introduce air or an air lock into the supply line from your aquahot or engine heater (espar, webatso, etc.)
Title: Re: Engine heater fuel supply point
Post by: buswarrior on March 20, 2018, 02:33:46 PM
How big is your fuel line?

Shouldn't be a problem...

I knew a mobile command unit that ran 2 x 8k generators and a DBW300 webasto off the same line, a regular outboard motor fuel priming bulb was in the line, (an option that solves SOOO many starting problems...) so nothing extraordinary in size...

Happy coaching!
Buswarrior
Title: Re: Engine heater fuel supply point
Post by: Jim Eh. on March 20, 2018, 06:19:50 PM
Just wondering if they had some kind of check valve in line to the Webasto?
Title: Re: Engine heater fuel supply point
Post by: richard5933 on March 20, 2018, 09:59:37 PM
Our 4106 had the Webasto and the generator both drinking from the same straw. Never a problem until I had a case of user-induced failure.

I took the Webasto out for service, and in order that the fuel lines didn't leak while it was out I just connected the ends together. At the time I didn't know they were sharing the lines with the generator. Then I ran the generator. Then the generator's fuel pump had the audacity to pull from the easiest place to pull - the air in the return line of the Webasto that was now connected to the feed line of the generator. Oops. And a Perkins is apparently a bugger to bleed air from. Took forever to get all the air out of the lines there. Lesson learned.
Title: Re: Engine heater fuel supply point
Post by: birdarchitect26 on March 21, 2018, 05:59:24 AM
It is a simple calculation really. Flow Rate = Velocity X Area. So in essence you just increase the flow rate by requesting additional velocity from the beginning portion of the line; if its cold you may be under the diesel flow threshold and starve an engine. I would take a look at what flow rate your generator and heater uses to avoid putting strain on things and cause unnecessary maintenance on a fuel pump. My personal opinion says 3/8" line will support any bus needs, 1/4" may be too small for more than just a genny. Never had an issue with too large a line.
Title: Re: Engine heater fuel supply point
Post by: luvrbus on March 21, 2018, 06:42:09 AM
It is best to have separate supply lines,I have saw some real problems over the years with owners using the same tap for engine, heat,and generators and the problems are not easy to solve with 1 tap,then again we all do it our way   
Title: Re: Engine heater fuel supply point
Post by: Bill Gerrie on March 21, 2018, 06:47:23 AM
You beat me to it luvrbus. I was going to say the same thing. Don't starve the engine or any other thing just to make it easier to install.   
Title: Re: Engine heater fuel supply point
Post by: Jim Eh. on March 21, 2018, 10:58:16 AM
But isn't it more fun that way?


Quote from: richard5933 on March 20, 2018, 09:59:37 PM
Our 4106 had the Webasto and the generator both drinking from the same straw. Never a problem until I had a case of user-induced failure.