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Thread: Variable speed pumps and air in basket at low speed

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    Variable speed pumps and air in basket at low speed

    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!
    77000L (20500 gallon) vinyl in-ground chlorine double roman pool, 35'x17', Hayward SP3200VSP, Jandy Lite2 LJ400N heater, Hayward S244TC filter, *deleted* Hayward chlorinator, Taylor CK1004FAS+CYA

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    JasonLion's Avatar
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    Re: Variable speed pumps and air in basket at low speed

    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.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

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    Re: Variable speed pumps and air in basket at low speed

    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.
    77000L (20500 gallon) vinyl in-ground chlorine double roman pool, 35'x17', Hayward SP3200VSP, Jandy Lite2 LJ400N heater, Hayward S244TC filter, *deleted* Hayward chlorinator, Taylor CK1004FAS+CYA

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    JasonLion's Avatar
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    Re: Variable speed pumps and air in basket at low speed

    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.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

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    Re: Variable speed pumps and air in basket at low speed

    I can't go lower than 1900 RPM on my Hayward VS 2300 pump or the heater service light comes on because of low pressure.
    20X36 IG vinyl (18,000 gal), 3 sheer descents, Max-Flo 1.5hp VS 2300, Aquarite T15 SWG, C3030 filter, 250,000 BTU heater, Sharkvac XL (Hayward equip)

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    susa's Avatar
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    Re: Variable speed pumps and air in basket at low speed

    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

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    mikespoolfl's Avatar
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    Re: Variable speed pumps and air in basket at low speed

    I have the hayward ecostar and usually the pump will try and reprime itself if it starts sucking air.
    Screen enclosed 17K gal 16x30 IG with Diamond Brite finish, elevated 4 jet spa with spill over, Twin dolphin fountain, Hayward Ecostar pump[ Pentair intelliflo VS, Filter Sta rite Posi-Flo PTM 100, Aqua Cal heat pump, Tiger Shark QC robotic cleaner.
    Stenner peristaltic pump model 45MPHP10, 15 gal storage tank. TF 100 with Speed Stir.

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    Re: Variable speed pumps and air in basket at low speed

    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.
    77000L (20500 gallon) vinyl in-ground chlorine double roman pool, 35'x17', Hayward SP3200VSP, Jandy Lite2 LJ400N heater, Hayward S244TC filter, *deleted* Hayward chlorinator, Taylor CK1004FAS+CYA

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    Divin Dave's Avatar
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    Re: Variable speed pumps and air in basket at low speed

    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
    Divin Dave,
    IG Vinyl, 15' x 30', 3 1/2' - 6' deep, Oval, ~15K gal, Intelliclor IC40, Intelliflo VS pump, Clean and Clear 420 Filter, auto-fill-disabled, Retrofit LED Color Light, Dolphin Nautilus Robot, TF100 Test Kit, Taylor K1766 Salt Test Kit, Tftestkit Pressure Gauge.
    www.tftestkits.net Experience- it's what's learned just after you needed it most !!

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    Re: Variable speed pumps and air in basket at low speed

    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?
    77000L (20500 gallon) vinyl in-ground chlorine double roman pool, 35'x17', Hayward SP3200VSP, Jandy Lite2 LJ400N heater, Hayward S244TC filter, *deleted* Hayward chlorinator, Taylor CK1004FAS+CYA

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    JasonLion's Avatar
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    Re: Variable speed pumps and air in basket at low speed

    Using larger pipe for the manifold is a good thing, but pipe size doesn't have anything to do with air in the strainer basket.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

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    Re: Variable speed pumps and air in basket at low speed

    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.
    77000L (20500 gallon) vinyl in-ground chlorine double roman pool, 35'x17', Hayward SP3200VSP, Jandy Lite2 LJ400N heater, Hayward S244TC filter, *deleted* Hayward chlorinator, Taylor CK1004FAS+CYA

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    Re: Variable speed pumps and air in basket at low speed

    Quote Originally Posted by Divin Dave View Post
    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
    Interesting...So you are running the pump 11 hours daily?? I guess at 950 rpms this is ok?? Thx
    20X36 IG vinyl (18,000 gal), 3 sheer descents, Max-Flo 1.5hp VS 2300, Aquarite T15 SWG, C3030 filter, 250,000 BTU heater, Sharkvac XL (Hayward equip)

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    Re: Variable speed pumps and air in basket at low speed

    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
    77000L (20500 gallon) vinyl in-ground chlorine double roman pool, 35'x17', Hayward SP3200VSP, Jandy Lite2 LJ400N heater, Hayward S244TC filter, *deleted* Hayward chlorinator, Taylor CK1004FAS+CYA

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