Mystery plumbing, what might these lines do?

[bmccarty]

I recently moved to a new home with a pool and I'm a first-time pool owner. I understand most of my plumbing system but I have 2 things I haven't yet figured out.

1) I have what seems to be an "extra" spa return line.

The line is hand-labeled by the previous owner as "spa return" and has been in the off position since I've owned the pool. There is another spa return that seems to function for all the jets in the spa and the spa seems to fully function even with the extra return turned off. I've tried turning on the additional return but I don't see any obvious effect from that.

2) I also have what looks to me like a drain pipe but I don't know if that's accurate and if it is I don't know how to use it; there doesn't seem to be any valve that controls it.

Here are plumbing photos. The 2nd photo shows the returns and the one marked "spa return(off)" is the one I'm wondering about. Any ideas what function it may serve? And the 4th and 5th photos show what looks like a drain line. It's the diagonal line coming out from the wall.

https://goo.gl/photos/SKLDjhXS64b6Du558

Thanks all,
Brad

 

[mas985]

Sometimes spas are plumbed with a separate return line from the spa jets. This is so that a second pump dedicated to spa jets can be used for improved performance. Also, if you want to just heat and filter the spa without the jets you can do that with this setup. I suspect the return is probably near the bottom of the spa.

 

[SoCalGuy]

The "extra" spa return allows you to divert some filtered & chlorinated water (via your chlorinator) to the spa when in "pool return" mode.

 

[bmccarty]

Sometimes spas are plumbed with a separate return line from the spa jets. This is so that a second pump dedicated to spa jets can be used for improved performance. Also, if you want to just heat and filter the spa without the jets you can do that with this setup. I suspect the return is probably near the bottom of the spa.

Bingo, that was it! It also answers the 3rd question I had on my plumbing and forgot to ask; "What is that opening near the bottom of my spa?". Very good because I was wondering if there was a way to get the heat without the bubbles and that's it. I noticed that when I open up this return and leave the other one to the jets also open, that the jets go off presumably because the pressure is reduced so that the venturi doesn't pull in air. Is there a "preferred" manner of using these 2 valves? I.e. would one normally have one or the other open but not both or does it not matter?

Thanks a bunch, another feature I didn't know I had.
Brad

- - - Updated - - -

The "extra" spa return allows you to divert some filtered & chlorinated water (via your chlorinator) to the spa when in "pool return" mode.

Thanks for the help! Looks like Mark found the right answer.

Gotta love the TFP site.

 

[mas985]

Is there a "preferred" manner of using these 2 valves? I.e. would one normally have one or the other open but not both or does it not matter?

For just general filtering, you would probably be better off bypassing the jets as they would tend to raise the PH. Unless of course you in the process of lowering TA which it would then be helpful.

 

[bmccarty]

For just general filtering, you would probably be better off bypassing the jets as they would tend to raise the PH. Unless of course you in the process of lowering TA which it would then be helpful.

Good point on raising the PH, thanks again for your help.

Any guess on my other mystery pipe that looks like a drain?

Have a great Sunday evening.

 

[mas985]

What is on the other side of that concrete wall?

 

[bmccarty]

What is on the other side of that concrete wall?

The bottom of the pool. The pool is built on a slope and the equipment pad is on the lower side about level with the bottom of the pool. All the equipment is below the waterline.

Sure seems to be a drain to me but I have no idea how to use it if it is.

 

[kadavis]

Usually the spa return is on the same side of the spa actuator valve as the pool return. That way in pool mode you get circulation through the spa and pool. Instead they set your spa return actuator partially open to get spa circulation. The way it is if you opened the spa return to circulate water and you wanted to use spa you would have to go back and manually close spa return to get all the action to spa jets. Also you should abandon the tablet chlorinated if your using it

 

[bmccarty]

Usually the spa return is on the same side of the spa actuator valve as the pool return. That way in pool mode you get circulation through the spa and pool. Instead they set your spa return actuator partially open to get spa circulation. The way it is if you opened the spa return to circulate water and you wanted to use spa you would have to go back and manually close spa return to get all the action to spa jets. Also you should abandon the tablet chlorinated if your using it

Thanks for your help too. I have recently abandoned the chlorine tabs for liquid chlorine and I'm loving the quality of the pool water.