Spa losing water to pool when pump off and is not check valve! Air pressure fixes it though. Clueless!

[bveratudela]

Hi,

For the past few weeks, I have been battling with losing water from the spa to the pool when the pump turns off unless I shut off the spa return line. I replaced two check valves I have and the problem persisted. When the pump is off and the spa return line is on, water will start coming out from the pool bubblers until the spa water level reaches below the spa return jets.

Today, I went outside to continue my inspection and decided to turn the whole system off and open up the chlorinator. Water in the chlorinator was sucked completely! I closed the lid and ensured the spa return line was open, and noticed water was no longer coming out from the bubblers.

I continued to experiment by turning the pump on with the chlorinator lid off until it was full of water, closed the lid, turned the pump off, and noticed water released from the pool bubbler. Opened up the chlorinator lid, water was sucked immediately, closed the lid, and no water was released from the bubbler.

I am currently running the pool without the chlorinator lid on just to see what happens when the pool turns off tonight. I have also turned the dial to 0 on the chlorinator so no water is flowing to it but at least let air to equalize pressure and not lose spa water. But my goal is to fix the problem now and am not sure what to fix.

Any thoughts on what the culprit is in a situation like this would be helpful. Thanks.

 

[Jimrahbe]

B,

I assume the Spa Return valve and the check valve are in series on the same pipe..

If so, the only thing that can be wrong is the check valve...

So.. Something is not right...

Please show up several pics of your equipment pad.

Thanks,

Jim R.

 

[bveratudela]

Pictures attached. A couple of things to note:

- No pipes have changed since before this issue started.
- The pipe with the blue handle is the old line to the cleaner pump which is no longer in use
- The manual valve on the pipe right below the blue handle is the spa return line (which when shut off, alleviates water from the spa coming back into the pool)
- The chlorinator lid is currently flipped and taped just to leave it open temporarily and let air pressure level with water pressure which appears to also fix the backflow of water from spa to pool when the pump goes off and spa return line is left open

 

[bveratudela]

I took a video of the sound the chlorinator makes when the pump goes off and chlorinator lid is open, which is when it sucks air. I can share that if needed.

 

[Jimrahbe]

B,

Thanks for the pics..

The whole purpose for the check valve marked "Heater Return" is to prevent the spa from draining down when the pump is off.

The fact that you can shut off the manual Jandy valve and "fix' the problem proves that the water has to be passing through the check valve. If the check valve is working, water should not be able to move backwards through it..

I can only assume that the check valve is not sealing like it should.. even it the guts are new. You want to make sure there is no glue or debris where the valve seat seals...

That said, let's see what @1poolman1 has to say... Maybe he has seen this before...

Thanks,

Jim R.

 

[bveratudela]

Right. I totally agree with your assessment on the purpose of the check valve. What perplexes me is why leaving the chlorinator lid open fixes it. Maybe the air pressure coming in from the chlorinator left open is greater than the water pressure from the spa return jets when the pump is off and therefore air pressure puts more force into the check valve to shut it off fully, and otherwise the metal spring of the check valve is too weak to fully close with the water pressure when the chlorinator lid is closed and no air goes in? Let’s see what @1poolman1 says. Perhaps he has seen this before. If not I can try replacing again the check valve which is new but costs $15 unless I go with the original Pentair which I replaced with Jandy but costs $80!

 

[ajw22]

If not I can try replacing again the check valve which is new but costs $15 unless I go with the original Pentair which I replaced with Jandy but costs $80!

Did you cut out and glue in an entire valve or just replace the internals into the existing housing?

If that is a Pentair check valve then you should replace it with Pentair parts.

The internals of different manufacturer valves are shaped slightly differently. Mixing manufacturers parts will not always seal properly.

 

[bveratudela]

We may be into something then @ajw22. The check valve at the top (the one that would stop water flowing back from the pool return jets) was replaced fully when the pipes cracked with a freeze in Texas, but the bottom one (the one that stops water flowing back from the spa return jets) was not. The check valve for that one was just replaced due to flapper damage but the whole thing has been there since the pool was built in 2016. I only replaced the lid with the flapper using a Jandy but the casing is the original Pentair.

I can try replacing it with a Pentair and spend $80 instead of $15 for the Jandy (I have been tempted to go down this path but haven't yet) or replace the whole casing with a Jandy too. My only final question before I go down this path is why would the air pressure seem to close it fully when the chlorinator lid is left open? Maybe I will let the chlorinator lid open for a few hours after the pump is off to see if the spa still loses water but at a much slower rate if the Jandy flapper does not fully close a Pentair casing. Will report back on my findings.

 

[bveratudela]

OK reporting back, I noticed water still dropped but definitely more slowly. I am going to replace the check valve with a Pentair one and hope that fixes the problem.

 

[ajw22]

When you get the Pentair flapper and remove the Jandy flapper look carefully at the shape of the flapper seal gasket. I think you will find them slightly different.

 

[1poolman1]

We may be into something then @ajw22. The check valve at the top (the one that would stop water flowing back from the pool return jets) was replaced fully when the pipes cracked with a freeze in Texas, but the bottom one (the one that stops water flowing back from the spa return jets) was not. The check valve for that one was just replaced due to flapper damage but the whole thing has been there since the pool was built in 2016. I only replaced the lid with the flapper using a Jandy but the casing is the original Pentair.

I can try replacing it with a Pentair and spend $80 instead of $15 for the Jandy (I have been tempted to go down this path but haven't yet) or replace the whole casing with a Jandy too. My only final question before I go down this path is why would the air pressure seem to close it fully when the chlorinator lid is left open? Maybe I will let the chlorinator lid open for a few hours after the pump is off to see if the spa still loses water but at a much slower rate if the Jandy flapper does not fully close a Pentair casing. Will report back on my findings.

Pentair check valve cannot use a Jandy assembly. The ports are different enough that it must be a Pentair.

 

[bdavis466]

When you have the chlorinator open you are breaking the siphon. If the chlorinator was lower than the spa, then water would be coming out of it when open instead of flowing back into the pool

 

[bveratudela]

I am writing to confirm and close this thread, as well as thank everyone for responding to it. The Pentair check valve fixed the problem. And yes the mould of the opening in the casing matched the flapper which was different from the Jandy flapper. Bottom line anyone facing this must replace the flapper with the same valve of the check valve casing.