What is this valve?

[CraigMW]

While I think I've pretty well figured out our pool plumbing, I just discovered an in-line ball valve in our deck that I believe must be part of the suction side of the plumbing for our pool. I have no idea what this valve is for. On the suction side, there are three suction lines at the equipment pad... skimmer, spa drain, and cleaner line. There are two Jandy 3-way valves, one of these is to control pool vs. spa suction (that connects to the inlet of he pump), and on the main pool side of that is a second 3-way valve that balances the suction from the skimmer vs. the cleaner line. However, I can't figure out the purpose of the deck 2-way (inline) valve.

Any guesses?

 

[JasonLion]

Is the pool old enough to have been renovated before? One possibility is that it relates to something that no longer exists. One approach is to change the position of the valve and see if anything happens.

 

[CraigMW]

Jason:

Interesting thought. I'm not entirely certain if the pool was renovated or newly built. My guess, based on its appearance and the equipment is that it was probably renovated about ten years ago (we purchased it two years ago). You might be right about the valve being from the original build, but it's PVC, not brass or copper, so I'm not sure. I'll try it out and see what it does.

Thanks!

 

[ROB N]

Could it be a valve to control the flow to the waterfall???

 

[CraigMW]

Hmm, interesting thought. The waterfall runs off a separate pump and I've never figured out where it gets its water from. It has a separate pipe coming up from the ground as well, so it doesn't look like its connected into the pool suction line. It could indeed be involved in that function. I'll have to check that out! The waterfall itself uses similar in line ball valves to control flow to various parts of the rocks that make up this water feature. Thanks for that because I probably wouldn't thought of that!

 

[Richard320]

This
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[CraigMW]

Richard:

Of course, I never would have thought of that! Some evil pool builder put that there just to temp us unknowing pool tweakers!