Variable speed pumps and air in basket at low speed

Jump to latest Follow Reply
B

benjydog

0
Jun 12, 2013
119
GTA, Toronto, Ontario
Hi everyone, finally made the plunge and upgraded to a VSP After many long delays and challenges, we finally got it running last night.

Once i got it to prime, it worked great at higher speeds, and so much quieter than my old Jandy Stealth and achieved full prime (no air)!

I then decided to set it at a low speed, 1725 rpm for the night. After 2 hours there was a 2" bubble of air in the pump. After running almost 12 hours, the air bubble was down to the top of the filter basket.

I have searched around here and found that it seems well documented that this happens due to many possible sources, including dissolved gasses in the water, but my question is has anyone else seen this lately (all posts were 2+ years old). My other question is should i be concerned if that if i run at low speed for multiple days, will the pump ever fully loose prime and be pulling air?

Finally, has anyone come up with a best practise for speeds/timings? Should i run ever 2 or 3 hours at a higher speed for 15-20 mins to purge the air?

Thanks!
 
It is completely normal for variable speed pumps to have some air in the strainer basket on the lower speeds. If everything is working, there will never be any air getting into the filter, just in the pump basket. If you are getting air accumulating in the filter then you have a suction side air leak.

For a normal pool, without a spa or pump powered cleaner, or waterfall, or anything like that, you want to run for about four to six hours on a fairly low speed. That speed should be the lowest speed where the skimmer still skims effectively, and your heater and/or SWG still work correctly, but in any case not below 1,000 RPM.

Higher speeds are needed for cleaners powered by the main pump, solar panels mounted above water level, priming the pump, manual vacuuming, water features, and so on.
 
JasonLion - always a help! Thanks for the quick reply. Running it at 1725 there was only 1psi on the gauge. Is there an easy way to tell if the air is getting into my filter? I incorrectly said filter in my original post, I should have said pump basket. I'm concerned that as time goes, more air (too much air) will accumulate in the pump and cause pre-mature burn out.

I haven't braved figuring out what speed my heater kicks in at yet. That might be a project for tonight (the water is a balmy 67 degrees). Right now it seems like my skimmer works well at 1725, but it may even work at 1000, but more time and testing is needed. My setup is very different, I have 2 floor drains (connected to 1 suction line) and 2 in my skimmer (separate suction lines), all of which are 1.5" to my pump. I was hoping to go to 1000rpm or lower cause the pump said it was using only 68 watts! 1725 was around 250 if I remember correctly.

Also, I shut off the pump when I left for work this morning because I want to see it fully reprime after being off for 12 hours, especially in the 3 minute prime I set on the pump. That way I can be comfortable running only 4-6 (or more) hours a day and trust it will prime without someone watching over it. I had too many problems with my old pump, so i'm a little cautious.

Thanks.
 
If there is too much air in the pump basket, air will get into the filter. If no air is getting into the filter, you are fine.

Most (not all) filters have an air release valve at the top to vent out air. If water comes out right away, there wasn't any air in the filter. If you don't have such a valve, it may be difficult to tell.

If you lose prime, without opening the basket, something is wrong.
 
we see that also on some of our family pools which all use Pentair IntelliFlo VF pump but the 15 GPM slow-mode automatically adjusts (randomly) by speeding up a little, air bubble disappears, then resumes running slowly for the next several hours.

tested this also in Manual Mode and dialed it down to just 700 rpm, got a very small bubble after couple hours and it was slightly larger the next morning
 
Thanks for all the replies.

Good news is after sitting 12 hours, it primed in 1.5 mins. It seems to start building an air bubble for me after 1 hour at 1725 rpm. I'll try another day raising it up over 2k to see if it will run without the bubble. Hopefully my heater is around that rpm mark.
 
My pentair intelliflo did something similar. For the first couple months after I got it, I was emptying the basket a lot and I would get a considerable air bubble in the basket about the size of a tennis ball or maybe a little bigger after it primed. I was constantly trying to figure out where it came from and I was contstantly releasing the air valve to bleed it out. Looking for suction leaks and whatever else.... I never did figure it out.

I havent had the lid off for a few months now, nothing in the basket to clean... and the bubble is for the most part now gone. It might be the size of a golf ball now. SO I am chalking it up to residual air or not good enough bleeding it off after opeining the lid.

Just for FYI, for 3 hrs a day I run 1600 RPM and for 8 hours day i run it at 950
 
  • Like
Reactions: CajunCoding
Thanks

So this morning, the air was a little more than yesterday, ie just below the top of the strainer but still above the inlet.

I'm wondering, the pump is 2" but all my 3 suction lines are 1.5". Should my manifold be all 2" after the 1.5" ball valves? Could part of this be that the manifold is 1.5" with an adapter to 2" right at the inlet?
 

Enjoying this content?

Support TFP with a donation.

Give Support
Thanks. So it sounds like this is pretty common and the new pump is smart enough to know it has to reprime. If I learn to trust the pump, timers etc, I just need to make sure priming time is long enough to purge the air on initial startup and periodically have the pump run at a higher speed during longer run times (ie 12 hours of low speed).

I also want to make sure that running at 3000rpm will not cause the same issue. Maybe I'll try that tonight as the pool is in desperate need of a vacuum.

I'll have to see how much the pipes and fittings are going to cost for me to try to up the manifold to 2". If it's not the source, I may hold off for now unless my installer agrees to do it at N/C.
 
Divin Dave said:
My pentair intelliflo did something similar. For the first couple months after I got it, I was emptying the basket a lot and I would get a considerable air bubble in the basket about the size of a tennis ball or maybe a little bigger after it primed. I was constantly trying to figure out where it came from and I was contstantly releasing the air valve to bleed it out. Looking for suction leaks and whatever else.... I never did figure it out.

I havent had the lid off for a few months now, nothing in the basket to clean... and the bubble is for the most part now gone. It might be the size of a golf ball now. SO I am chalking it up to residual air or not good enough bleeding it off after opeining the lid.

Just for FYI, for 3 hrs a day I run 1600 RPM and for 8 hours day i run it at 950
Click to expand...

Interesting...So you are running the pump 11 hours daily?? I guess at 950 rpms this is ok?? Thx
 
I think 1k rpm is to low for my skimmer. The pool seemed clean but in the skimmer I didn't see any swirling. Also seems like 3200+rpm is louder than my old pump, but it could be my imagination as I've been listening to this new one at 1725.

Ran it for almost an hour yesterday at 3200 and it seemed to not grow air. Going to try again today if I can
 
You must log in or register to reply here.
Thread Status
Hello , This thread has been inactive for over 60 days. New postings here are unlikely to be seen or responded to by other members. For better visibility, consider Starting A New Thread.
Top Bottom
Back
Jump to latest Follow Reply