Suspicious of a suction side air leak

[dleonard1122]

I just opened our pool 3 days ago. I've been running the pump 24/7 at low RPM like I always do since then. This morning I checked on things and noticed the filter was making a gurgling sound. I set the pump to max rpm and a bunch of air was pushed out of the system. It took about a minute to fully clear out the plumbing. Now I'm suspicious of a suction side air leak.

We built the pool last year and opened for a few months last fall. It was 'normal' for me to have a small air bubble in our pump basket. My pH rose faster than I thought it would, but I assumed that was just related to the SWG and running the pump 24/7. It might be a red herring, but now I'm wondering if that too is a result of a suction side air leak I've had the entire time?

I am going to start troubleshooting the usual spots at the equipment pad. I know i put silicone grease on the pump basket o ring before I installed it. My suspicion is actually with the Jandy valve that controls my main drains. I lost my air lock over winter and I'm thinking that might be the culprit.

Based on some searches it seems like shaving cream was recommended. Just regular foaming barbasol out of a can?

How urgent is this repair? Am I safe to keep things up and running like normal for the time being? I plan on just running the pump on high for a minute or so a day to clear things out until I find the leak and get it fixed.

 

[1poolman1]

I just opened our pool 3 days ago. I've been running the pump 24/7 at low RPM like I always do since then. This morning I checked on things and noticed the filter was making a gurgling sound. I set the pump to max rpm and a bunch of air was pushed out of the system. It took about a minute to fully clear out the plumbing. Now I'm suspicious of a suction side air leak.

We built the pool last year and opened for a few months last fall. It was 'normal' for me to have a small air bubble in our pump basket. My pH rose faster than I thought it would, but I assumed that was just related to the SWG and running the pump 24/7. It might be a red herring, but now I'm wondering if that too is a result of a suction side air leak I've had the entire time?

I am going to start troubleshooting the usual spots at the equipment pad. I know i put silicone grease on the pump basket o ring before I installed it. My suspicion is actually with the Jandy valve that controls my main drains. I lost my air lock over winter and I'm thinking that might be the culprit.

Based on some searches it seems like shaving cream was recommended. Just regular foaming barbasol out of a can?

How urgent is this repair? Am I safe to keep things up and running like normal for the time being? I plan on just running the pump on high for a minute or so a day to clear things out until I find the leak and get it fixed.

A small air leak will not cause major issues, though it is good to find it. Air should be released through the filter's internal air screen. Be sure the pump lid O ring is lightly lubricated and the union in front of the pump is snug. Make sure the drain plugs on the pot and body of the pump are tight as well.

 

[dleonard1122]

Alright, I've done some troubleshooting and at this point I have more questions than answers.

I re-lubed the pump inlet o-ring, the pump strainer basket o-ring, and the pump strainer basket drain o-ring. I'm confident all of those are not leaking at this point.

Tonight I took apart the Jandy valve for my main drains and re-lubed that. It was a bit sandy and the main body o-ring didn't look positioned quite right when I took it apart, but that could have just been the way it fell when I disassembled it. I cleaned it all out, re-lubed all of the o-rings, and put it back together. The seal that blocks off the outlet was a bit scratched up, but in my head that couldn't cause an air leak, it would just allow water to bypass.

I started the pump back up and purged the system of air and will wait until tomorrow morning to see if the air is back.

Before I came back in though, I did a test to see if there was air inside of the filter again and was surprised at what happened. I had the pump running at my normal low operating speed of 1250 rpms. I opened the air relief valve and air was actually sucked into the filter, like what would happen when I turn the pump off and open the air valve when I want to get into the pump basket for instance.

I was surprised that air was sucked in, and not pushed out. I guess maybe it makes sense if the pump isn't pushing out enough pressure to lift the water in the filter up to the pressure relief, that the weight of the water could overcome it, drawing air in as the water level in the filter rises. Is this normal? If it's not, what gives, because as it is now I feel like I could actually be getting a 'suction side' air leak from my filter.

Sorry if I'm rambling, but at this point I'm second guessing my knowledge of the pool system and how things are supposed to operate. I also don't even know if I truly have an air leak or if this is all some red herring that I'm chasing. Last year it was normal for my to get a relatively small bubble of air in my pump strainer basket. This year I feel like what I've seen is a little bigger than I remember, but maybe I'm imagining things. I don't know that I remember my filter filling up with air last year, but I can't say I remember checking for it either.

Apologies to anyone who had to read this whole thing, but if you made it this far I'd appreciate if you could set me straight.

 

[dleonard1122]

This is how big the bubble in the pump strainer basket got overnight, and it's representative of how big the bubble stays. In reading about other suction side air leaks, it sounds like some folks have it so bad that the entire baskets of water. I never have that issue.

I jumped the pump up to 2000 rpms and it cleared the bubble away. I then opened the pressure relief valve on top of the filter and there was enough pressure in the system to push any air out the top and then water.

Part of me thinks this is just a symptom of running the pump at such low rpms, but I'm still not convinced I don't have a suction side air leak.

 

[dleonard1122]

@Texas Splash it sounds like you have experienced similar situations here.

Does what I've described above match your experience? Have you ever noticed your filter tank getting partially or even half full of air? What rpm do you bump your pump up to in order to purge the air?

 

[Texas Splash]

Does what I've described above match your experience?

For now - yes. That last pic with your last statement in Post #4 sounds quite typical, especially for VSPs. Just be sure to check it daily to purge any trapped air and to ensure the pump pot water level doesn't drop significantly.

 

[Newdude]

My old bubble was the size of yours. With the new pump/ pool, it fills half the lid, but never grows past that. It obviously continues because an air leak wouldn't decide enough is enough and it should seal itself now.

11 years ago with my first pool, my PB told me that any burrs or interior glue drips in the plumbing would cause cavitation as the water rushed past it. I never gave it any thought past that until landing here.

The pump is obviously the first place it has to collect, and the filter the second place. Experimenting with my new bubble last year, the filter also never grew past a 3 second burst of air from the air relief valve, whether it was a day, or 2 weeks. If I study my pump bubble, I can see tiny bubbles break off from it, swirl around the basket and get sucked downstream. I imagine it does the same inside the filter. Anything more than it's 'sweet spot' of air gets moved along and the ever changing bubble appears to never change.

This has only been noticed since VS pumps and low speed operation. Unions before the pump and pump lids have always been used. and I suspect it was always a thing, but the SS pumps forced enough water to not allow the bubbles to collect, and it went unnoticed. There are many systems out there without unions, yet everybody seems to notice the bubbles, leading at least some credibility to the imperfect plumbing connections before the pump. If you ramp up your RPMs high enough, it will clear, not because it stopped, but because the flow is such to force the air downstream.

I spent lots of time last year with goggles watching the returns when the SWG was not producing, and there would be small stray bubbles coming out, but just long enough between them that I wouldn't notice without looking for them. Had I just walked by looking for a few seconds, I wouldn't see any and would go about my way thinking it wasn't happening.

I suspect the same thing was happening on my old pool but I didn't notice.

 

[Turbo1Ton]

View attachment 484056

This is how big the bubble in the pump strainer basket got overnight, and it's representative of how big the bubble stays. In reading about other suction side air leaks, it sounds like some folks have it so bad that the entire baskets of water. I never have that issue.

I jumped the pump up to 2000 rpms and it cleared the bubble away. I then opened the pressure relief valve on top of the filter and there was enough pressure in the system to push any air out the top and then water.

Part of me thinks this is just a symptom of running the pump at such low rpms, but I'm still not convinced I don't have a suction side air leak.

This appears 100% normal to me. I had a small suction leak on a fitting and my pump basket would drop 1/4 of the level or more. And during higher speeds you could see 1000's of tiny bubbles churning around.

If you do have a suction side leak, it is miniscule and I wouldn't waste a lot of time trying to find it.

--Jeff

 

[dleonard1122]

Thanks all, this makes me feel a lot less paranoid. I'll continue to monitor and just make sure my pump is scheduled to ramp up daily to a high enough rpm to clear things out and 'reset' the system clear of air.