Raised spa with only 2 main returns (spa and pool return labeled in red). I've included a pic of my setup for reference. I have an in-line backflow preventer on the spa return (light teal circle) which I think is bad and not working correctly. I don't even see the flap inside opening or closing when I turn the jandy valve and open flow to the spa return. Yesterday I decided to close off the return flow to the spa completely (normally I keep it open a little) to test and see if it would still loose water with that jandy valve (yellow circle) closed off to the the spa return. I figured if it stopped losing water, then it was definitely a faulty backflow preventer. At first it look like it was working and not losing any water, so I decided to let the pump run and wait overnight to see if the water level dropped in the spa...but when I came home today, the water in the spa had dropped about 5-6". Do you think it could also be a bad jandy valve not sealing off properly? If the jandy valve would seal off properly, wouldn't it not make a difference if the backflow preventer (light teal circle) was faulty because it would still be stopping backflow at the valve itself right? I may be wrong, I'm by no means an expert on any of this...so please let me know your opinions! TIA
Trying to figure out why spa (raised) is losing water
- Thread starter CajunGuy
- Start date
Be sure the valve in front of the pump (suction) is completely closed. Even a little off from completely closed will allow a spa to drain through the valve back to the pool.
Open the check valve and see if the flap is deteriorated or has something stuck in it.
Can a jandy valve turned to spa off with only return water running to pool also act as a backflow preventer from the spa (when the pump is off) since the off is to the spa return? I just assumed it since water was being diverted to the pool, it would also not allow waterto backflow through the jandy valve. Maybe my thinking isn't correct. I'm starting to think it's just a faulty backflow/check valve (teal circle). I don't even see the flap move open when I open flow to the spa.
Also, are you talking about the jandy valve that is circled in yellow? If so, that's my main return line. That jandy valve (yellow circle) was completely closed with the "off" to the spa side when it lost water in the spa. The spa return line (red letters that says "spa return") is the only line going back to the spa, so it has to be either the backflow preventer (teal circle) or jandy valve (yellow circle) that is bad right?
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A picture of all the plumbing would help. The pool/spa return valve is partially open to the spa (allows for overflow when filtering). If the check valve is bad, it will allow water to leak back to the pool through that valve.
Note that your valves are Pentair in case you ever need to replace the internal parts, Jandy and Pentair are different.
I'll post a pic of the entire setup later this afternoon and label everything. In the pic the pool/spa valve was open, but that was CLOSED OFF TO SPA when I tested it (I took the picture a day later). If the check valve is bad it would allow water to leak back through up towards the spa/pool jandy valve (yellow circle), but if that jandy valve was closed off to the spa, wouldn't it not allow water back throughat that point (so on essence stopping the spa from losing water)?
Unfortunately, you are trying to apply logic to a pool that has water going where it shouldn't. If it can happen to a pool it will.
Have you check the flapper in the check valve for damage/debris? Do not use a power screwdriver to reassemble.
If the diverter was completely closed to the spa, then yes, water should not be able to leak past if it gets by the check valve. But, the diverter could have a bad seal (not very common in more modern valves). The builder could have used a "solar" valve that was in stock, or accidentally, in place of a regular valve. They have a design that allows for that kind of leak back for solar systems when the system shuts off, Pentair exclusive design.
You could still have a leak at the suction valve (in front of the pump) that may not be completely closed or have a bad diverter.
Ahhhh thanks for the explanation. I'll start with the check valve and remove the flapper to inspect it. I actually don't even see the flapper open up when I open flow to the spa...is that normal? I'm thinking it might be stuck somewheres in the middle (halfway open).
Poolman, could a small air leak in my T-piece (plastic is cracked where the pressure gauge screws into) on top my sand filter cause the spa to lose water? I just noticed today that it is cracked and has a very small air leak coming from the crack. I could hear it when my pump was turned off.
@1poolman1, could a crack in the plastic of the air bleeder assembly (small air leak I can hear when pump is off) where the pressure gauge screws in at cause the spa to slowly lose water?
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