Backflow preventer placement?

[jmoore15]

Have a 2013 Z3 and crossed my vents and drains. Still have a lot of passive draining from my bags. So...after filling the bags I shut off the ball valve at the pump...problem solved. So my question is should I put the backflow preventer near the fill on the top of the bag or before the Y that splits the flow to the hard tank/bag???

[Ewok]

Before the y, I had the same problem and a 1 way check valve on my fill lines solved it.

[jmoore15]

Perfect. Thanks ewok.

[zogzila]

One thing to keep in mind is the back pressure on the check valve. At first I put mine down low near the pump and sometimes had trouble getting the water flowing. Reason being the water left in the line would hold the flap closed (too much back pressure in this case). I would have to shake the check valve to get water flowing.

I moved them higher on the line and problem solved.

Good luck.

[ChrisSnow]

could you not fit the check valve before the pump? this way you would keep the lines primed all the way.

[BCRider]

It would be too much hardware to try and put before the pump. As long as your pump is below the water line priming shouldn't be much of an issue.

[h2osk8er00]

I just had to do the same thing... My bags are cross drained but vented on the same side.. so I had to put some check valves there as well.. All is working great now except I am taking on a lot of water in the rear engine vent... Saw some thread regarding this last week where people were putting a plexi-glass plate so I am going to try and work something like that.