Came back home yesterday after a 5-day Thanksgiving trip to find my pool over-filled with water and my elevated spa completely empty. Everything was normal (of course) when I left on Monday. I read several threads about spas draining in this way, and they mostly describe a failing check valve on the return side as the typical culprit. However, I think that my case is a little different and I'm hoping for some advice. Here are the pertinent details:
1. The suction side is plumbed like this: spa return + pool return into a Pentair 3-way automated valve, then directly into the VS pump. No check valves of any kind. Prior to this, the pool return line is fed by a line from the skimmer and the cleaner. Cleaner is 100% off (I use a robot instead). No other above-ground piping on the suction side. Sorry I didn't get a pic today, but can snag one tomorrow if needed.
2. When I have the pump on and set the suction to pool and return to spa, the spa is filled, but it seems slower to fill than would have been typical in the past. When it eventually rises high enough to spillover, the volume is less than half the normal spillover volume. And the entire time, the water in the spa swirls. If I set the solar heat to on, the spa will slowly drain. Call it maybe 1/2 inch down over the course of a few minutes. Meanwhile, if I go over to the skimmer, remove the basket, and put my hand over the return pipe to the pump, I barely feel any suction. And with the solar on, the circulation from the pool is a pittance, if anything.
3. If I shut off the pump, the spa drains rapidly... all the way to its floor drains. I didn't time this, but the spa will be bone-dry within probably 30 minutes or less. And with the pump off, I can see the water flowing through the skimmer back into the pool... and the flow is so strong that the skimmer basket (even with the rock I have in there for weight) is displaced out of the seat. I believe all the spa water is returning to the pool via the skimmer; I don't think any is returning via the return lines.
4. The spa's floor is higher than the pump, which is higher than the pool. Spa jets run on a separate pump and circuit so they wouldn't seem to be relevant.
So, what it seems like to me, is that for some reason the 3-way valve on the suction side is drawing from both the pool and the spa, even though it's set to draw from the pool only. And when the pump shuts off, the spa water just pours back through it until the spa is completely empty. Or, I have some obstruction in the pipe between the skimmer and the pool, and that casues more of the pump's suction to pull from the spa (through what could be a worn 3-way valve that doesn't seal well). And as for why the solar changes the spa level... I think it's just that the pump has to push the water up to my roof and also runs at a slightly different speed, reducing the suction and overall flow rate enough that the pump doesn't return water to the spa fast enough to keep it from slowly draining.
Does that seem right? If so, then I suppose I can just take that valve apart and see what's wrong, such as a worn seal. But it seems strange that a worn seal would allow such a huge volume of water to pass through the valve in such a short amount of time. Any other thoughts or troubleshooting suggestions before I potentially mess this up further by taking apart that valve?
Thanks very much!
1. The suction side is plumbed like this: spa return + pool return into a Pentair 3-way automated valve, then directly into the VS pump. No check valves of any kind. Prior to this, the pool return line is fed by a line from the skimmer and the cleaner. Cleaner is 100% off (I use a robot instead). No other above-ground piping on the suction side. Sorry I didn't get a pic today, but can snag one tomorrow if needed.
2. When I have the pump on and set the suction to pool and return to spa, the spa is filled, but it seems slower to fill than would have been typical in the past. When it eventually rises high enough to spillover, the volume is less than half the normal spillover volume. And the entire time, the water in the spa swirls. If I set the solar heat to on, the spa will slowly drain. Call it maybe 1/2 inch down over the course of a few minutes. Meanwhile, if I go over to the skimmer, remove the basket, and put my hand over the return pipe to the pump, I barely feel any suction. And with the solar on, the circulation from the pool is a pittance, if anything.
3. If I shut off the pump, the spa drains rapidly... all the way to its floor drains. I didn't time this, but the spa will be bone-dry within probably 30 minutes or less. And with the pump off, I can see the water flowing through the skimmer back into the pool... and the flow is so strong that the skimmer basket (even with the rock I have in there for weight) is displaced out of the seat. I believe all the spa water is returning to the pool via the skimmer; I don't think any is returning via the return lines.
4. The spa's floor is higher than the pump, which is higher than the pool. Spa jets run on a separate pump and circuit so they wouldn't seem to be relevant.
So, what it seems like to me, is that for some reason the 3-way valve on the suction side is drawing from both the pool and the spa, even though it's set to draw from the pool only. And when the pump shuts off, the spa water just pours back through it until the spa is completely empty. Or, I have some obstruction in the pipe between the skimmer and the pool, and that casues more of the pump's suction to pull from the spa (through what could be a worn 3-way valve that doesn't seal well). And as for why the solar changes the spa level... I think it's just that the pump has to push the water up to my roof and also runs at a slightly different speed, reducing the suction and overall flow rate enough that the pump doesn't return water to the spa fast enough to keep it from slowly draining.
Does that seem right? If so, then I suppose I can just take that valve apart and see what's wrong, such as a worn seal. But it seems strange that a worn seal would allow such a huge volume of water to pass through the valve in such a short amount of time. Any other thoughts or troubleshooting suggestions before I potentially mess this up further by taking apart that valve?
Thanks very much!
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