Sand filter waste port question


Jul 13, 2008
I bought a used Pentair SD40 sand filter off of craigslist and hooked it up to a 3/4 hp pump. It is now running but there is a small amount of water coming out of the waste port. I don't have anything hooked up to it yet to close it. Is that normal? I was just going to attach some pvc and a valve to close it, or is there a gasket leaking in the multivalve port?

If it is a gasket...(I don't see any gaskets listed for this multiport anywhere on the internet, nor at the pentair website, only the entire multiport assembly seems for sale)...any problem with just attaching a valve to keep it from leaking?


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Apr 1, 2007
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or is there a gasket leaking in the multivalve port?
Most likely. There is a gacket inside the valve called a spider gasket or wagonwhell. I'm surprised it doesn't show on the diagram.

The valve onto the waste port is a clever fix but perhaps replacing the spider gasket is better long may fix some other issues as well.
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