Pool Losing Water Only When Pump Is Running

[jsnobles]

Guys/Gals,

I have an issue with a new liner just being replaced in my pool. This will be a long post, but I could really use some advice/knowledge. The pool only leaks water when the pump is running(no water is coming out the backwash). The people that installed my liner said that it must be an issue with the plumbing to the pool. The pool was fine last year when I shut it down (no leaks when the pump was running). I had American Leak Detection come out and do a pressure test this morning. I will include a couple of video clips if I can, but I will also explain the procedure they did. So, they plugged the skimmer, and pump basket and then performed their test. I have two return lines, and they capped off both when testing. The deep end return checked out fine, but the shallow end return showed leakage. ALD said that it is because the return fitting is cracked, and that water is leaking behind the liner because they didn't use a gasket behind the fitting. The pool installers said that the liner itself is good enough to be a gasket. To give you an idea of how much is leaking, I have filled the pool to the top screw on the skimmer (the one closest to the top), and let it run overnight several times. In about 10 hours or so, it has leaked down to the lower level of the skimmer inlet and I have to turn the pump off of course. The pool installers seem to think there is a leak in the skimmer line to the pump. It is about a 7 foot stretch of PVC underneath the concrete deck, but ALD says the skimmer line is fine. When the pool is off, the water doesn't go down in the pump basket at all. I understand there could be a leak in this piping, but wouldn't the water level go down a noticeable amount? Also, there is suction on the skimmer line, not pressure, so I don't understand how that much water could be leaking out of this line when the pump is running. Please, give me some thoughts/ideas on what you think the issue may be. If you need additional details, I will gladly provide them. Thanks!!

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[Texas Splash]

So you're losing water only when the pump is on, so that would indicate a pressure side leak (from the filter to the return jets). If it was from the suction side (pool skimmer to the pump, you would have air getting sucked-in while running, and/or lose water when the system was turned-off. So if ALD is confirming that a return jet fitting is cracked or was not properly sealed with a gasket during installation, I would hold the builder to that on top of the fact you had to pay out-of-pocket for that expert service. Very frustrating. Once some people get your money, they don't want to hear from you again. That is a pet peeve of mine. :grrrr:

 

[jsnobles]

So you're losing water only when the pump is on, so that would indicate a pressure side leak (from the filter to the return jets). If it was from the suction side (pool skimmer to the pump, you would have air getting sucked-in while running, and/or lose water when the system was turned-off. So if ALD is confirming that a return jet fitting is cracked or was not properly sealed with a gasket during installation, I would hold the builder to that on top of the fact you had to pay out-of-pocket for that expert service. Very frustrating. Once some people get your money, they don't want to hear from you again. That is a pet peeve of mine. :grrrr:

Agreed, Texas Splash. However, this is not a new pool. It is very old...maybe 20-30 years old. Yes, only when the pump is running am I losing water. ALD confirmed that the pressure side returns back to the pump are not leaking. However, as I stated, the liner installer is saying that there may be a suction side leak from the skimmer to the pump (It's about 7 feet or so). I will attach some pictures. Did you see my video links that I posted?

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Also, if it were a suction side leak from the skimmer line to the pump, wouldn't the pump not prime, or not be able to hold a prime? In essence what I mean is that I can fill the pool up to the correct level according to the skimmer screws, turn on the pump, and it doesn't lose a prime. It runs fine with a little swirling action that is noticed in the top of the pump basket which is normal for my pump/system. The pump runs fine until the water level gets depleted to the bottom of the skimmer, and then it starts sucking air, of course. If the installer of the liner is correct in his assumption, that's a heck of a lot of water to lose in a suction side line, which if my math is correct, about 500-700 gallons in a 10-12 hour timeframe. That's a LOT of water to be lost for a line to lose water that is pulling it into the pump.......not pushing it into the return jets. Am I correct on this?

Another thing, the liner installer said that he has never had to use a gasket on a return jet fitting. They say that the liner itself is a good enough gasket. While this does hold some merit, I don't think this would always be true.

 

[Texas Splash]

I did watch the videos, and I think we agree on the problem however the terminology is getting mixed-up a bit. For example,

ALD confirmed that the pressure side returns back to the pump are not leaking.

there are no "pressure side returns" back to a pump. The water returning to the pump (poolside skimmer to pump) is your suction side. I can tell from the vids that the pressure test administered on the return jets shows a compromise around one of those return jet fittings. That would explain the water loss while the pump is running as you noted.

the liner installer is saying that there may be a suction side leak from the skimmer to the pump (It's about 7 feet or so). I will attach some pictures.

I disagree with the liner folks. If that were the case, you would have either lots of air getting "pulled" into the suction line (which you do not), or possibly even have some dirt sucked in as well. Then water would drain out of that suction line (skimmer to pump) when the system was off.

If it were a suction side leak from the skimmer line to the pump, wouldn't the pump not prime, or not be able to hold a prime? Possibly.

Depends on how bad the leak was.

So I agree with ALD and believe there's a leak around the return jet (pressure side) where they installed the liner. There's no argument there, you have it on video. The liner installers need to fix it if it's still under warranty.

 

[jsnobles]

I did watch the videos, and I think we agree on the problem however the terminology is getting mixed-up a bit. For example, there are no "pressure side returns" back to a pump. The water returning to the pump (poolside skimmer to pump) is your suction side. I can tell from the vids that the pressure test administered on the return jets shows a compromise around one of those return jet fittings. That would explain the water loss while the pump is running as you noted.

I disagree with the liner folks. If that were the case, you would have either lots of air getting "pulled" into the suction line (which you do not), or possibly even have some dirt sucked in as well. Then water would drain out of that suction line (skimmer to pump) when the system was off. Depends on how bad the leak was.

So I agree with ALD and believe there's a leak around the return jet (pressure side) where they installed the liner. There's no argument there, you have it on video. The liner installers need to fix it if it's still under warranty.

Thx, Texas Splash. Sorry for the confusion on my terminology, they go back to the filter through the skimmer and filter before it gets to the pump to be recirculated into the pool.


Agreed on the liner installer issue. Yes, it's still under warranty. It is a brand new liner that they installed last Friday (Tara Liner, and I registered it with the manufacturer on their website). They are bringing out new fittings tomorrow, as they have to special order them because of my pool age, the fittings are supposedly threaded different than pools these days and are not stocked by local pool stores. Let me know any other additional comments please.

Let me ask you this......couldn't the liner installer pop out the liner above the return jet that is obviously suspect, and then turn on the pump to see if water is going behind the liner rather than back into the pool as it should be? It seems like a quick determination for the issue at hand, doesn't it?

 

[Texas Splash]

Let me ask you this......couldn't the liner installer pop out the liner above the return jet, and then turn on the pump to see if water is going behind the liner rather than back into the pool? It seems like a quick determination for the issue at hand, doesn't it?

Perhaps. I'm not an installer, but I would hope they could see something at that point to help confirm.

I'm glad to hear they are responding to your warranty work. I'm sure it's a pain to go through this right after the initial install, but that's probably better than if it happening next season and they try to wiggle out of it. I hope the repair goes well and swift. Good luck!