Air in the pool

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Anotherdayanotherproblem

Member
Jun 26, 2022
21
West End NC
I have seen other threads on this issue but have a few questions. For the past year my pool pump fails to prime after being off overnight. I can self prime it and it works but there are air bubbles coming out the jets, air in my pump basket and I hear air in my sand dollar filter as well as coming from my fountain feature. it all points to a leak on the intake side. So I had the line from the filter basket to my two skimmer baskets pressure tested by a leak detection company. The said both lines were holding pressure. (They tested for 10 minutes at an ungodly PSI) I only use one of the skimmer baskets Because the other does not fill the basket enough when the diverter valve is set to that side. I assumed it had a clog several years ago, long before my current bubble problem And if they tested it from the filter basket and the diverter was leaking to the defunct side it would have not held pressure. Next I replaced the filter basket lid, clamp and o-ring. Lubed the o-ring. All is tight. I am waiting for a strap wrench to arrive so I can take the the coupling off the front of the basket. The pressure test would not have been able to test that joint because the air bladder used was inserted in the line past it) my pool store advised me to use silicone on the entire joint including the threads rather than plumbers tape. Is this advisable? As well is it perceivable the the joint on the out port of the pump leaks as well and I should do that one too? I truly can not find visible any leaks on the non suction side (no water). It would seem obvious that you would see water leaking on that side. BTW the sand dollar is new, and the filter valve is new. Any ideas thanks
FYI update 2024
If anyone has this problem……..It turns out my multiport valve was the culprit. It was leaking air back into the system via the backwash hose. Replaced it completely and all the priming problems went away.
 
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That is a hard post to understand but I can possibly help.

What you describe is surely a suction side leak. The suction side is from the skimmer throat to the impeller. It is often hard to find but most always easy to fix once found.

I would NEVER use silicone on a swimming pool joint.

So help me understand, are you trying to find that air leak? (Keep it simple for this senior citizen! :) )
 
Yes, I am trying to isolate an air leak. My pump looses water level overnight and has to be manually primed each morning. Air in the pool, filter basket and sand dollar filter.
Line has been pressure tested from the filter basket to the skimmers. No leaks. New filter basket lid, clamp ring and lid o-ring. Filter. Only place not yet tested is the connection at the front of the filter basket. Waiting for a slip wrench. I will abandon the silicone per your advise. Is there any other reason it would lose water level and not prime overnight such as a leak after the pump? I don’t visually see any water leaks on that side.
 
Welcome to TFP!

Does the pump eventually prime and purge air after start up? After priming are you still seeing bubbles in the pump basket?

You may have a leak on the pressure side of the plumbing, after the pump. Pool plumbing is designed to be water and air tight so it hold pressure when the pump is off. Even a small leak will allow air to enter the systems which will drain the water back to pool water level. Think about holding a straw out of your drink with you thumb over the top. It holds water, but as soon as you take you thumb off the straw, water drains out of the straw.

Instead of looking for a water leak, listen for an air leak. Shut down the pump and get close to the plumbing. Listen carefully for the sound of hissing air. Both times I had a pressure side leak, I tracked it to the air relief valve on top of my filter. The o-rings that seal the valve are wear items. Check drain plugs on the pump and heater and any diverter valves on the return side.
 
Rancho Cost-a-Lotta said:
Welcome to TFP!

Does the pump eventually prime and purge air after start up? After priming are you still seeing bubbles in the pump basket?

You may have a leak on the pressure side of the plumbing, after the pump. Pool plumbing is designed to be water and air tight so it hold pressure when the pump is off. Even a small leak will allow air to enter the systems which will drain the water back to pool water level. Think about holding a straw out of your drink with you thumb over the top. It holds water, but as soon as you take you thumb off the straw, water drains out of the straw.

Instead of looking for a water leak, listen for an air leak. Shut down the pump and get close to the plumbing. Listen carefully for the sound of hissing air. Both times I had a pressure side leak, I tracked it to the air relief valve on top of my filter. The o-rings that seal the valve are wear items. Check drain plugs on the pump and heater and any diverter valves on the return side.
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No it only primesif I manually fill it. The pump basket is full of air. I replaced the gaskets on the suction side diverter valve. I replaced the top of multiport valve. I did not replace the bottom half being it would need to be cut out and PVC parts are hard to get right now. But it came with a brand new spider gasket and o-rings. I replaced the bleeder valve stem and o-ring. And you are the first person to confirm it could be a pressure side leak. Everyone says suction side only. Thank you. I will go do another listening test.
 
Anotherdayanotherproblem said:
And you are the first person to confirm it could be a pressure side leak. Everyone says suction side only. Thank you. I will go do another listening test.
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...if the pump eventually primes and runs without sucking air. If it never primes, it's likely on the suction side. Let us know if you can track something on the pressure side.
 
Anotherdayanotherproblem said:
No it only primesif I manually fill it. The pump basket is full of air. I replaced the gaskets on the suction side diverter valve. I replaced the top of multiport valve. I did not replace the bottom half being it would need to be cut out and PVC parts are hard to get right now. But it came with a brand new spider gasket and o-rings. I replaced the bleeder valve stem and o-ring. And you are the first person to confirm it could be a pressure side leak. Everyone says suction side only. Thank you. I will go do another listening test.
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I did another listen test. I turned off the filter and immediately the water gurgled back down in the filter basket. After that there is no hissing on either the suction side or the pressure side. The air problem pre dates the multiport top replacement so I don’t think it is there. It pre dates replacing the intellichlor chlorinator, so that is probably not the problem. the pump basket lid is definitely not leaking. The glued PVC joints sound and look good and you think they would drip if they leaked. I will spray them all with soapy water and look again. That really leaves the threaded connector on the pump pressure side, the threaded connector on the pump basket suction side Or maybe the pump itself? It’s a 10 year old pump. NPS leak detectors pressure tested the pool lines. I don’t know which direction they went. I would hope they tested from the skimmer basket back, turn the multiport to closed and wait 20 minutes. But I don’t know how they did it. All I know is they said there were no in ground leaks.
 
Rancho Cost-a-Lotta said:
...if the pump eventually primes and runs without sucking air. If it never primes, it's likely on the suction side. Let us know if you can track something on the pressure side.
Click to expand...
Rancho Cost-a-Lotta said:
...if the pump eventually primes and runs without sucking air. If it never primes, it's likely on the suction side. Let us know if you can track something on the pressure side.
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Thanks
 
Rancho Cost-a-Lotta said:
...if the pump eventually primes and runs without sucking air. If it never primes, it's likely on the suction side. Let us know if you can track something on the pressure side.
Click to expand...
This has confounded me for a long time. I went out again and turned the pump off…the water did not gurgle out of the filter basket! It stayed full! I sprayed all of the joints couplers, valves, everything with soapy water. Watched and listened…no detectable leaks. Turned the filter back on, it primed and has less bubbles in the basket but still some. How can this be? I could go out tomorrow morning and would be empty and not prime. And once I prime it be full of air. The next day it could be filled and prime. Leaks don’t come and go. Unless it is truly something wrong with the multiport. I loath having to redo all the PVC to put the new bottom half of the mutiport onto the sand dollar. But if I have to.
 
Let's clear up "prime". To me, a pool circulatory system is primed when the air is (virtually) completely pulled from the suction side of the system......between the skimmer throat and the impeller.

To me, it sounds like you are describing a slow leak that's lets air into the system allowing the water to drain back to the pool. That leak can take many hours and it can actually be anywhere in the system (pump off) but it shows itself eventually by allowing water out of the pump basket back to the pool

Is that what's happening?

It can be a pressure side leak but not while the pump is running.

Pump on, water is pushed out of a pressure side leak. Normally quite visible. Pump off, that pressure side leak can then allow air to seep back into the system and can drain your pump basket.
 

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duraleigh said:
Let's clear up "prime". To me, a pool circulatory system is primed when the air is (virtually) completely pulled from the suction side of the system......between the skimmer throat and the impeller.

To me, it sounds like you are describing a slow leak that's lets air into the system allowing the water to drain back to the pool. That leak can take many hours and it can actually be anywhere in the system (pump off) but it shows itself eventually by allowing water out of the pump basket back to the pool

Is that what's happening?

It can be a pressure side leak but not while the pump is running.

Pump on, water is pushed out of a pressure side leak. Normally quite visible. Pump off, that pressure side leak can then allow air to seep back into the system and can drain your pump basket.
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Yes and no. It can be fine for a week. Enough water in the basket each day that it primes on it’s own, yet lots of bubbles in the basket and pool. And then you go out one morning and it has lost most of its water in the basket And I have to manually prime it. Today for instance, I tuned it off and all the water gurgled out of the basket and back into the pool! I turned it on and it primed itself. twenty minutes later I went out and did it again. No gurgling, the water stayed to the top of the basket. As you noted it would at first glance be a slow leak that happens overnight. But then how come one time the basket empties out, the next it doesn’t. Perhaps there is more than one problem. A slow leak on the suction side and a bigger problem on the pressure side??
 
When you pump is running do you see continual bubbles either in or passing through the pump basket?
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"Yes". Then that is a pretty definitive suction side air leak. Find that leak and you will solve your problems. Did you read the article on Suction Side Leaks in Pool School? It may help you track it down.
 
duraleigh said:
"Yes". Then that is a pretty definitive suction side air leak. Find that leak and you will solve your problems. Did you read the article on Suction Side Leaks in Pool School? It may help you track it down.
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Yes, great article. I still may have more than one problem. As you and most others have said most defiantly the air is a suction side issue and I’m suspecting the coupling at the front of the filter basket assuming that when they pressure tested the lines to the pool they knew what they were doing And they were correct that the diverter and line underground held pressure. As for the water in the basket gurgling out when I shut the pump off and at other times staying full. I suspect something on the pressure side. My 20 year old tech from the pool store said just run your backwash longer, it’s channeling in the sand. Not sure why that would cause it. But he‘s had a lot of experience. Hmm, well at least four years. Thanks again. I will post what I find later in the week
 
As for the water in the basket gurgling out when I shut the pump off
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Again, that is very likely due to the suction side air leak. Pump RUNNING, it continues to push air into the top of the filter (air from the suction side leak). When the pump stops, however, that air has pressurized the top of the filter, pushing the water backwards out through the pump.

Sorry, but the pool tech knows NOT about which he speaks! :mrgreen:
 

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