Air in pool filter every day

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  #1  
Old 01-01-18, 12:59 PM
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Question Air in pool filter every day

This is new. My pool filter, a Pentair Clean & Clear Plus 420, is filling with air. At any time while the pump is running, I can open the relief valve and air will emerge for up to 30 seconds until water starts coming out. I'm running the IntelliFlo pump at 2000 rpm, which in the past has been sufficient to keep everything running smoothly with no air intrusion.

Water level in the pool is OK. In fact, everything I can see is OK. There are no visible water leaks or even drips. I see a few air bubbles at the top of the leaf pot, but that has always been the case in the 5.5 years I've owned this pool.

The only thing which has changed lately is that my solar thermal guys repaired a small leak in the solar system and then turned off the solar, emptying the panels and shutting the valves. So that should be completely out of the system and not part of the problem.

I'm baffled as to where the air is getting in. My first thought was the relief valve itself might be sucking in air, but it doesn't appear to be.

I'd appreciate any thoughts on troubleshooting.
 
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Old 01-01-18, 01:44 PM
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When the pump isn't running.... water empties out of the tank and back into the pool.
When the pump restarts.... water gets trapped in the tank but eventually will work it's way out.

I haven't had any problems caused with air in my tank.
 
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Old 01-01-18, 03:40 PM
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Originally Posted by Pjmax
When the pump isn't running.... water empties out of the tank and back into the pool.
When the pump restarts.... water gets trapped in the tank but eventually will work it's way out.
That's not what's happening here. I'm getting air in my filter tank while the pump is running.

I also don't believe the scenario you describe ever occurs with my setup.

My pump is slightly below pool water level. I have water in the leaf pot at all times, even when the pump has been off overnight.

The system is ostensibly airtight, meaning water could not flow back to the pool due to vacuum. Water only empties from the tank when the relief valve is open.

And my filter manual suggests air can indeed be trouble. "Air entering your filter is dangerous and can cause the lid to blow off. Correct any conditions in your filtration system that allow air to enter the system."

I think my next step is to ensure the leaf pot lid is airtight. Any other suggestions welcome.
 
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Old 01-01-18, 03:47 PM
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If air is getting into the system it has to be before the pump. Possibly a broken underground line.
 
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Old 01-01-18, 03:56 PM
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What psi reading is on your gauge on your filter? It might help to bleed the air out until a steady stream of water comes out. 10-15psi is usually the goal.
 
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Old 01-01-18, 04:32 PM
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Originally Posted by jreed841 View Post
What psi reading is on your gauge on your filter? It might help to bleed the air out until a steady stream of water comes out. 10-15psi is usually the goal.
Iíve been bleeding the air twice a day. Pressure is 9 psi, which is normal at 2000 rpm with clean filters.
 
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Old 01-01-18, 05:39 PM
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And you checked all the gaskets and o rings lubed and made sure their tight?
 
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Old 01-01-18, 07:57 PM
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Originally Posted by jreed841 View Post
And you checked all the gaskets and o rings lubed and made sure their tight?
Yes, did that with no luck.

Looking closely, I suspect the clear plastic lid of the leaf pot may have a hairline crack. It's possible it was over-tightened either by me or one of my ever-changing crew of pool guys. Is it possible to have a crack so tiny that air can get sucked in but water doesn't leak out?

Anyway, it occurs to me that this pump is 5 years old and parts do wear out, so I ordered a new lid and a new o-ring. If throwing cheap parts at it doesn't work, I'll have a pro take a look at it.
 
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Old 01-02-18, 06:36 AM
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It's not worth the time to track down every possible pinhole in the suction-side of the system.

A) You can install an automatic "burp valve" on the top of the tank.
Use a "T fitting" to add the vent ( in addition to the pressure gauge.)
"Air vent valve" is the technical term. Cost is about $10-20.

B) In my setup, I have an air vent in the system, but I use a "T" fitting and valve on the top of the pressure tank
to provide a bypass to a kitschy "spitting dolphin statute".

This means, the spitting dolphin acts as an analog pressure gauge, and a presssure relief valve.

When the filter is clean, the pressure is low, the dolphin spits about 5'.
When the filter needs to be cleaned, the pressure is high, the dolphin spits about 20'.
 
  #10  
Old 01-07-18, 07:28 AM
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OP.......Before starting.......when you look down into pump basket thru clear top.....do you see an air bubble ?
 
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Old 01-12-18, 05:56 PM
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Originally Posted by YaddaYadda View Post
OP.......Before starting.......when you look down into pump basket thru clear top.....do you see an air bubble ?
Yes, there always seems to be a little air in the leaf pot.
 
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Old 01-12-18, 06:21 PM
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That air bubble is not uncommon. My Hayward super pump basket cover always has air trapped in the top.

The system is ostensibly airtight, meaning water could not flow back to the pool due to vacuum. Water only empties from the tank when the relief valve is open.
Not necessarily correct. If you had a hole/leak in the suction line halfway between the pool and your filter..... the water could drain from the leak back to the pool so that it was empty and from the leak to your filter would still be under vacuum. This is a real common problem. However, since your lines and filter are all below the water level.... not extremely likely but still possible. A leak could draw air in and yet not leak water.

I've personally never had or seen a leaking cover. I guess it is possible. You could put a light bit of vaseline on the gasket or try spraying between the cover and the pump with a water bottle when running. You'd hear the air getting sucked in.
 
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Old 01-13-18, 12:52 PM
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Well, I replaced the clear leaf pot cover and my air-sucking problem seems to be gone. I now get only a tiny blast of air from the relief valve before water spews out.

The only other thing that changed is that it rained, a rarity here in the SF Bay Area. I wonder if that could have had an effect on something underground somehow.

Finally, I always understood that petroleum jelly is bad for rubber o-rings, so I always use silicone grease.
 
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