Mysterious valve by filter and main drain not working

[raventy]

Hey guys,
So I just moved into a house with a pool and I'm trying to close it for the summer and as such, need to drain the water below the skimmer. I turned the jandy valve by my filter from the skimmer to what I thought was the main drain and started the pump up. It sucked water this way at a flow rate about half of what id see during normal filter running till the water level started dropping below the skimmer, then it stopped all together. Thinking maybe I was sucking water from the skimmer this whole time, I turned the jandy valve back to the original setting and watched where it sucked from. I saw it suck water from the skimmer so I set it back to the other setting and noticed it no longer sucked from the skimmer, so it must be the main drain except now its no longer sucking.

Anyone have any suggestions as to why my main drain stopped or what to do?

Also, I noticed a strange valve located after my jandy valve but before my filter pump. Any idea what this is for? For the life of me I cant figure out why it's there. See the attached picture of it.

Thanks!!

 

[Divin Dave]

Hi,
yes, that valve alternates between the skimmer and the main drain.

"" id see during normal filter running till the water level started dropping below the skimmer,""

Most likely what happened is the valve is not air tight and once the water got below the skimmer, it started sucking air and lost prime.
Thats my best guess.

 

[raventy]

hhhmm when the main drain lost suction, I noticed my skimmer still had water trapped in it, so I would have thought that if there was still some suction from the skimmer, the water would have drained.

As for the mysterious valve, if you look at my picture there is a third line running into my pump after the jandy valve. Any clue what that is?

 

[Divin Dave]

I guess I may have misunderstood. I thought the water was below the skimmer. Air getting in the line was my best guess.

Have no clue what that thing off to the side is.

 

[pabeader]

Connection for suction side cleaner?

 

[EVChargeGuy]

Can you confirm how many Skimmers & drains you have? Just one of each?
It looks like the mysterious valve may have had some sort of handle at one time?
I guess when you winterize you can open up the valves union and blow air directly into that line and see where the air comes out, if at all?

 

[OldPoolMan]

That is a Hayward Mfg ball valve. It is on a suction line to somewhere and you'll need to investigate further to see where it pulls water from.

 

[raventy]

Thanks for all the replies! Let me clarify a few things:

1.) I did drop the water below the skimmer, but the skimmer itself still had water hanging out in it so I could tell if it was sucking from there or not.

2.) I have 1 skimmer, 1 main drain, and 2 returns.

3.) Turning the Jandy Valve to position 1 sucked water from the skimmer. Turning the Jandy valve to position 2 made water suck from what I assumed was the main drain (only other place in the pool I can see what draining from). If I take a wrench and turn the mystery valve, my skimmer will stop sucking. Turn the mystery valve back, and all is good.

4.) No matter what I do, I can't get the main drain to start sucking water anymore.

Really wish I knew what the heck that mystery valve is for! Why on earth would it bypass the Jandy valve? I thought all skimmer lines and drains would go into or before the Jandy, not directly into the pump?

 

[OldPoolMan]

Have you checked all around the pool for another suction port? Like a vacuum line for a pool cleaner? Its obviously sucking water from somewhere and when turned on would reduce suction from your skimmer.