Return question

[Mydoghasfleas]

Have a question before I order some plumbing hardware. I have an Iwaki MD100RLT return pump. It’s rated for 2000GPH @4’. The input and output are 1”. Should I use 1” PVC then For the return? And if so, how far under the water line should I drill for a 1” bulkhead? I was thinking 1/2” under water line...but had a hard time finding exact details. Thanks!

 

[foxt]

For the hole location, it's a matter of preference. I usually put mine an inch or so below the water line and use locline to route it up a bit and then point the outlet down, with the anti-siphon hole in the section that I directed upwards.

You did not say what size tank, or target flow rate. 1" line will work just fine, and depending on the target flow rate and how far above the pump the outlet is, you might even be able to reduce it to 3/4".

 

[Mydoghasfleas]

@foxt Tank is about 220 gal. Target flow rate maybe around 1200 GPH. Thanks for the reply! I found at 0.5” below water line, with a 1” bulkhead, I would have ~ 15 gal of possible backflow. I wouldn’t want any more then that because my sump is kind a small due to a limited footprint.

 

[foxt]

I have a 220g with two 1" returns at opposite ends, so I would definitely not reduce the 1" below that.

Did you know that you can decrease the amount of water that siphons back to the sump when the pump shuts down by drilling a small hole for a siphon break in the part of the return that sits in the tank?

 

[Mydoghasfleas]

@foxt Plan for dual 1” returns as well. I have seen some examples, but not familiar with how it works.

 

[foxt]

The siphon break is actually pretty easy.

Say you extend your return outlet into the tank with some locline. You just drill a very small diameter hole in the locline horizontal with and below the water line. When the pump is running, a small stream of water will shoot out of this hole, but it is ok because you placed the hole so that the stream is under water.

When the pump shuts down and the water starts siphoning back through the return, when the water level reaches the level of the hole the siphon sucks air and eventually breaks. I like to use locline because I can raise the level of the siphon break well above the actual outlet of the return, but you don't need to do it that way ...

 

[Goodair]

What size sump do you have, as long as it can hold the extra water that gets siphoned back, thats what is important. (Nozzle position and siphon breakers will impact this)

 

[Billdogg]

^^^What all of them have said about the siphon breaks^^^

As for the dual returns - run one line up to someplace behind the tank, and use a "T" fitting and a few 45's/90's to get the PVC to where you want it. Easy!

And do yourself a favor - buy at least 2 extra of each fitting - it''ll save you a run back to HD/Lowes in the middle of your project. You can always return them if you don't use them. Personally? I have boxes marked by size from 1/2" CPVC up to 2" PVC with a selection of pieces/parts. You'd be amazed just how handy that is!