Main drain winterizing

  • Last Post 26 October 2020
Austin posted this 08 October 2019

Hey guy, first time closing my pool by myself. This is an older pool with 2 holes at the bottom of the skimmer. One going to my pump(which is already blown out, and one going directly to the main drain at the bottom of the pool. I have a gizmo in the hole going to the pump, but am worried about what to do with the line going to the main drain. Do I just add antifreeze? Or is that not good enough? Not sure if there is a way to blow this line out or make sure it stays okay during winter

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InyoRob posted this 08 October 2019

The line from your skimmer to the main drain is called the equalizer. There isn't an easy way to blow out that line. What you can do is put "foam rope" down the equalizer line and then cap it with a plug or gizmo.

The foam rope is a closed-cell polypropylene product. It's also called a closed-cell backer rod. Push as much of the rope in as possible. If the water freezes in that pipe, the foam rope should absorb the expansion.

Image result for closed cell foam rope

Austin posted this 08 October 2019

Thanks for the reply. So no need to worry that the line is still filled with water?

InyoRob posted this 09 October 2019

According to the pool professionals we've talked to, leaving water in the main drain equalizer line is ok as long as you follow the tips mentioned previously.

You'll still want to winterize everything else like normal. That includes dropping the water level below the skimmer.

Rogers posted this 25 October 2020

Thanks much for your explanation above and on Youtube!  Is it difficult to get the foam rope out while opening the pool in Spring?  Or does it just pop out?  

InyoRob posted this 26 October 2020

It will pop-out a little bit once you remove the plug.