Puzzling Pump air bubble issue?

fOxdiddy

Member
May 27, 2021
5
Ottawa, ON
Hi. Long time lurker, first time poster. This is a really weird one ...

Last year we got a brand new Pentair pump for our inGround pool. We never had issues with air in the old pump basket before. However, our old pump was a Hayward super pump and was waaaaay over powered for our pool. It was 3 + HP and one speed, so it ran like heck 100% of the time (and cost a bundle in energy). We switched to the Pentair because it's multi-speed and runs at 2000 rpm mostly, which is much slower and does the job.

Issue is, I almost immediately noticed that as the pump runs on the lower speed, over time little air bubbles start to collect in the pump basket. They almost build up over time. Running the pump on prime (which increases the RPM to 3200) gets rid of them. Then they accumulate again. Example, the pump was full and air free after backwashing on Saturday. It ran that way until yesterday when I noticed a Loonie sized air bubble at the top of the pump basket. I stopped it, ran it on prime, now there is no again.

When you turn the system off, the lines will hold prime. The air bubbles do not get worse. We had a power failure recently that lasted 12 hours, the lines held prime perfectly throughout.

I've noticed the air gets worse when either skimmer basket is clogged or the sand in the filter needs to be backwashed. In fact, if the basket is clean and the sand is backwashed, I can go three or four days before I see the air bubble begin to return in the basket. It would seem to me that should this be an issue with the lines, 1) I wouldn't be able to hold prime, certainly not for 12 hours +. 2) running the pump on a higher speed would introduce more air to the basket, not remove it.

I mentioned this issue to the pool company that installed the pump, they provided a new O-ring for the basket. That didn't do much.

Notes: my sight glass is missing its seal and my pressure gauge is broken. (COVID is hampering my ability to replace either). I can also hear what sounds like sucking / suction / air sound in or around the multi-port. I do have a Jandy valve on the return side of the filter it splits the return into a Y and redirects water to the pool returns, the water falls or both. I suspect that's been leaking for a while (internally, pushing water into the other line, no signs of exterior leakage) but I don't think it's relevant to this, as it's on the return side and I never see air bubbles coming from the return jets (actually I have once, but the filter basket was clogged right up with Spring plant residue).

Could this be a sign of a bad spider seal in the multi-port (which is now 9 years old)? Any other hypothesis about what this may be?

Thanks in advance.
 
Last edited:

cowboycasey

Gold Supporter
LifeTime Supporter
TFP Guide
Jul 3, 2013
8,536
Southern OK
Pool Size
15000
Surface
Vinyl
Chlorine
Salt Water Generator
SWG Type
CircuPool SJ-40
Welcome to TFP :)

That is normal, no really it is for VS pumps... The way I stop the issue is run it up to 1600 rpm for my SWG and that gets rid of the bubble.. Right now I am only running 2 hours that high.. then it is good for the rest of the day... I am only running 12 hours a day so the next morning it kicks up to 2200 rpm for startup...

When I was running 24 hours it was doing it more...

Why this is happening I do not know, when or if I run it over 2000 rpm it never happens but down at 800 rpm it will do it...
 

cowboycasey

Gold Supporter
LifeTime Supporter
TFP Guide
Jul 3, 2013
8,536
Southern OK
Pool Size
15000
Surface
Vinyl
Chlorine
Salt Water Generator
SWG Type
CircuPool SJ-40
just make your pump do a 5 minute 2500 rpm 2 times a day and you will be good :)

Or shut it off for 5 minutes 2 times a day and make it prime again..
 
Aug 11, 2021
4
Massachusetts
Welcome to TFP :)

That is normal, no really it is for VS pumps... The way I stop the issue is run it up to 1600 rpm for my SWG and that gets rid of the bubble.. Right now I am only running 2 hours that high.. then it is good for the rest of the day... I am only running 12 hours a day so the next morning it kicks up to 2200 rpm for startup...

When I was running 24 hours it was doing it more...

Why this is happening I do not know, when or if I run it over 2000 rpm it never happens but down at 800 rpm it will do it...
Holy crud, your post is a godsend. I have been hunting for a ghost leak on the suction side with no luck, and am about ready to put my paver deck in, so I am very stressed out (I really don't want to start digging!). I see the exact symptoms described in the post above. When I run my IntelliFlo at 'low' speed, I get a slowly building air bubble over several hours. When the speed is turned up, the bubble quickly gets pushed out. Is there any 'formal' documentation anywhere about this issue? Thanks!
 

cowboycasey

Gold Supporter
LifeTime Supporter
TFP Guide
Jul 3, 2013
8,536
Southern OK
Pool Size
15000
Surface
Vinyl
Chlorine
Salt Water Generator
SWG Type
CircuPool SJ-40
Welcome to TFP :)

Just us normal people that check our equipment all the time and are obsessed with pools and everything involved with pools.. Stick around TFP and you will become one also :)
 
  • Like
Reactions: Newdude

Newdude

Gold Supporter
TFP Guide
Jun 16, 2019
10,384
NY
I named my bubble Fred. I would greet my old friend anytime I was checking things at the equipment pad.

I have no idea why Fred stayed relatively small and only in the curved part of the pump cover. Maybe the pump reprimed itself every other day or so, but he never grew enough to be concerned.
 

cowboycasey

Gold Supporter
LifeTime Supporter
TFP Guide
Jul 3, 2013
8,536
Southern OK
Pool Size
15000
Surface
Vinyl
Chlorine
Salt Water Generator
SWG Type
CircuPool SJ-40
I have been running at 1200 and 1400 rpm and with a prime every morning at 0630 and no longer have a bubble.. Mine will come back when the temp drops and I drop the RPM back down to 800 or so :)
 

ferretbone

In The Industry
May 24, 2016
112
tx
Yeap what all the above said. Tiny bubbles that get biggers over time on medim or low settings is a non problem I'd love to have. It's coming from the lid, suction nipple or union, or a suction side jandy. In that order. Lube the lid oring or replace, seal the nipple while the pump is running, and lube or replace the jandy orings.. Or turn your pump up full speed for a few hours and take a nap, have a beer etc. Small town problems bud.
 

Enjoying this content?

Support TFP with a donation.

Give Support