Return line - 90 elbow - where to drill to break siphon

User1 · Jan 30, 2018

Where would one drill a hole in a return line to break siphon? I know it is under the operating water line and is a small hole - say 3/16" - and I am guessing just above the outlet hole? I've attached a image - hopefully it will help.

I've not drilled a hole to break the siphon before but need to this time, or add in a check valve (which I may also do), because the sump over flowed even when I was within my high/low water line. I am safe if I don't but keep the sump on the lower waterline but prefer it a bit higher.

View attachment 20180128_182650.jpg

Edit: Hmm...not sure why the image is sideways on the site but normal on my PC. I'm sorry.
Edit 2: Forgot to say thanks.

lapin · Jan 30, 2018

I did mine 3/4" under the water line. I did not want water to squirt out above the water so I angled it so water would squirt towards the bottom of the tank. I had a lot of room in my sump for tank water if the pumps were turned off.

User1 · Jan 30, 2018

Thanks. So water will actually exit the hole during normal operation? Makes sense. Thanks for the angle tip. I didn't think of that.

Idoc · Jan 30, 2018

Drill it at the height where you want to stop the DT water from going any lower. The idea to angle the drill downward so the water shoot down during normal operation is a good idea. Just don't drill it on the top of the pipe or you will have a big mess...cuz yes, water is going to exit this hike during normal operation.