Hi,
I have a 15-18 year old in ground plaster swimming pool in the Las Vegas, NV area. It also has an overflow spa attached. The pool has returns from the main drain and skimmer baskets of the pool (and from the spa) , goes through the pump, then a cartridge filter, then a gas heater and then can return to the pool or spa. There is a valve that can be turned to route the return water through a in-floor cleaner or through the eye-ball returns. I understand all of this equipment and how it works. However, there is another valve that I do not know what it does. Its near the in-floor cleaner side of the equipment, so I assume it has something to do with the return water.

Its the item in the foreground of this photo. It consists of 3 pipes that come up out of the ground. there is a 3-way valve in the middle, that in order to turn, you have to dig the rocks out of the way because it turns downwards. On the pipe on the right side it has an Ortega check-valve. You can unscrew the right end. so basically water can press it open and go down, but not come back up the right most pipe. I have no idea what this does. I have no idea if the handle is in the correct position or not. The rest of the equipment had pool labels on it with wording like "CLEANER" or "SPA" but this had nothing (or it got painted over or scraped off years ago).
In the background, you can see the pool in-floor cleaner stuff as a reference. The valve that turns the in-floor cleaner on is over to the left of the heater (out of view in the photo). here are photos of those valves:


Any ideas? My concern is that this might be some sort of drain or something and its in the wrong position. I've turned it both ways and removed the check valve and water doesn't really come out of this. I haven't tried it with the cleaner on. i don't usually use the floor cleaner as I have a suction hose robot that does a better job of vacuuming the pool of leaves and dirt.
thanks and let me know any questions you may have.
I have a 15-18 year old in ground plaster swimming pool in the Las Vegas, NV area. It also has an overflow spa attached. The pool has returns from the main drain and skimmer baskets of the pool (and from the spa) , goes through the pump, then a cartridge filter, then a gas heater and then can return to the pool or spa. There is a valve that can be turned to route the return water through a in-floor cleaner or through the eye-ball returns. I understand all of this equipment and how it works. However, there is another valve that I do not know what it does. Its near the in-floor cleaner side of the equipment, so I assume it has something to do with the return water.

Its the item in the foreground of this photo. It consists of 3 pipes that come up out of the ground. there is a 3-way valve in the middle, that in order to turn, you have to dig the rocks out of the way because it turns downwards. On the pipe on the right side it has an Ortega check-valve. You can unscrew the right end. so basically water can press it open and go down, but not come back up the right most pipe. I have no idea what this does. I have no idea if the handle is in the correct position or not. The rest of the equipment had pool labels on it with wording like "CLEANER" or "SPA" but this had nothing (or it got painted over or scraped off years ago).
In the background, you can see the pool in-floor cleaner stuff as a reference. The valve that turns the in-floor cleaner on is over to the left of the heater (out of view in the photo). here are photos of those valves:


Any ideas? My concern is that this might be some sort of drain or something and its in the wrong position. I've turned it both ways and removed the check valve and water doesn't really come out of this. I haven't tried it with the cleaner on. i don't usually use the floor cleaner as I have a suction hose robot that does a better job of vacuuming the pool of leaves and dirt.
thanks and let me know any questions you may have.