Question about my plumbing setup

[Breakthecycle2]

I seem to be having an issue here. When I shut off my return pump to feed, the water continually drains, overflowing my sump. It happened twice and now it's happening more and more. I keep an eye on it now. I found the issue, one of my return lines is backflowing into the sump. If I take the return stream and lift up out of the water it stops. Each return has a schedule 80 ball/union valve on it. Does anyone have any ideas why the valve is allowing water to flow back down?

 

[143MPCo]

You need a siphon break on the return lines to break the back flow of water.

 

[Breakthecycle2]

I didn't do the plumbing, but I never had this issue until recently. It never overflowed. What is a siphon break..lol.

 

[143MPCo]

You can achieve this a few ways but, the simplest is drilling a small hole in the return lines at the top just before the returns enter the water line. Depending on placement you will want the drill so the breaks are submerged or will run the risk of injecting micro-bubbles.

 

[143MPCo]

What is a siphon break.

 

[143MPCo]

I never had this issue until recently. It never overflowed.

Check that you don't already have one... they become clogged over time and need to be cleared.

 

[Breakthecycle2]

Check that you don't already have one... they become clogged over time and need to be cleared.

What becomes clogged?

 

[Squid]

Ball valves are used to control flow not prevent backflow. A check valve is what is used to preven backflow if you do not want to make a siphon break hole or raise the return output.

 

[143MPCo]

What becomes clogged?

lol, the anti-siphon holes.