"Mystery" T--what is this thing?...

[spishex]

That's interesting that the pressure only went up to 20 psi. I'd double check two more things before deciding to cap it off:

- Are there any plugged ports anywhere in your pool? It could be a pressure side cleaner line.

- Try what you did with the valve again, but this time close off the main drain line on the suction side of your pump. It's possible the mystery T returns to the main drain, but with that line open for suction you could get bad hydraulics with no pressure build up, a lot like you saw.

And check around the yard for a capped 3" stub anywhere. Could have run a fountain or something at one point that was later removed.

 

[Magnew]

OK I went to the site and made a donation. Best money I ever spent!

Thanks all you guys and gals!

Mike

 

[Magnew]

No plugged ports anywhere.

When I did the test, the main drain suction line WAS closed all the way. Just pulling from the vacuum line and partial skimmer.

Can find no capped stubs anywhere in the yard.

 

[mas985]

My guess is that the line connects to the main drain. Some solar installers do that so that you can redirect the warmer solar water return through the main drain to the bottom of the pool. If the main drain suction line is closed, the return water would go to the main drain. With the main drain suction open, it would just create a partial loop.

 

[Magnew]

OK, that's interesting. The pool's too cold to go in to check that, but if I was getting any flow to wherever it's going, wouldn't I see some movement in the bubble in my strainer basket?

 

[mas985]

If you set the suction valve to cleaner only (remove the cleaner from the line) and open the valve between the main drain and skimmer so they are connected, you might see if you can feel water coming out of the skimmer. But you would have to close off the return valves as well.

BTW, if that line is connected to the main drain, it may be contributing to the VRV bubble problem by lowering the return pressure. Closing off that line would raise the pressure in the panels a little bit and might help along with the other changes you are planning. If you can aim a return downward toward the deep end, that should be just as good as returning through the main drain.

 

[Magnew]

Ok, Mark I did just exactly as you described in the post above, finally.

Their was no water coming out of the returns to the pool or spa, at least none that I could feel.

In the skimmer, there was the tiniest bit of suction. I put a piece of string on a pole and stuck it down by the main drain, and the string did not move.

This is driving me nuts, and is the obstacle I need to overcome in order to install a SWG. I do not have enough free pipe and space left after I cut out my Rainbow chlorinator, to install the salt cell, unless I deal with this dang Mystery T somehow (as in I need to cut it out).

I am open to any comments or suggestions as to how to proceed.

 

[spishex]

When you ran it as described did you check the cleaner line to see if you felt suction there? If there's none then the line is dead or plugged and I'd be comfortable capping it off; if you feel strong suction then there's water going somewhere and you'd want to further investigate.

 

[Ohm_Boy]

I think I'd go ahead and pipe around it, like this...[attachment=0:1qfaolne]pipearound.jpg[/attachment:1qfaolne]
While I had everything off and out of the way, I'd dig down and if need be, extend that big underground pipe straight up or cap it. Then I'd be in business while I decided what to do with it.

 

[chiefwej]

My only thought is if the water flow is up out of that pipe. I have a similar pipe comming out of the ground that is a return from my gas heater loop. Mine is a bit more obvious because there is a check valve right where it comes out of the ground.

 

[Ohm_Boy]

Well, like I say.. if it was me, I'd go ahead and isolate it. Then, assuming I couldn't just pull it straight out of the ground or hit the bottom with a long pole, I'd look at extending it straight up a foot or so and valve it so that I could attach a hose, maybe a gauge, and see where it goes or if it is sealed. In the meanwhile, I would have already created a place for the new SWG to go, and I'd have full flow to my pool.

 

[Magnew]

Spishex, I will give that a try tomorrow.

Ohm boy, thanks for the idea--I may do just that. I'm gonna dig a foot or two before I do anything. Maybe I'll find a check valve or something.

I'd hate to just cap it off and just go on not knowing. That thing looks like it was planned, and had some expense just in the T and connectors. Surely it did something. I would feel a lot better knowing what it was. My luck, I'll cap it off and the house will collapse!

Thanks everybody.