Originally Posted by DennisTD
I would think the overflow hose would be connected to the top of the tank. If that is the case I don't see how it could siphon. That can only happen if the overflow is running down into the tank. I wonder if Bullet Bob has some insight as to how the overflow is connected.
I can tell you exactly how it's attached in my Sierra. It's drilled into the side of the fresh tank with the bottom of the fitting about 1.5" below the top of the tank with the fill right next to it. You fill the tank, the fill pushes water to the backside of the tank, then once water comes out the over flow you turn it off. The water pushed to the back of the tank levels out and now you have water flowing out for ten minutes, usually below the full sensor.
And every time you turn, water will flow out.
And every time the trailer leans a little, even more will flow out.
So it doesn't really siphon in the true sense, but it looks that way.
I fixed mine with a T valve and a loop of hose draped over my LP tank. Now I can fully fill the tank and I won't lose any during travel.