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Thread: How to gauge proper START/CLEAN DE Filter settings with a variable speed pump?

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    How to gauge proper START/CLEAN DE Filter settings with a variable speed pump?

    Folks,

    I have a Pentair FNS PLus 48 DE Filter....

    My understanding is that you should measure your flow rate pressure on the top gauge then set(rotate) the Start Dial to that pressure, this will automatically determine the Clean Setting which is approx an increase of 10PSI.

    I get all this....but whenever I switch to a different speed, (higher) it usually increases the pressure, throwing my START/CLEAN targets out of whack. How do you all approach this?


    Should I only concern myself with the normal operating pump speed pressure (this is the speed that I am currently running at most of the day, 1700RPM for approx 12hrs) I will also have my booster pump running at 2200rpm 2hrs a day to run my pressure side Kreepy Krawler Racer cleaner. And I will also randomly run my pump a few hrs a day at 3100RPM to increase circulation and aeration when needed.


    I just want to make sure Im doing this right and really understand when my Filter needs a back washing....thnx
    Design 14x26 (10,000 gal) in ground vinyl pool, 2 Wide Mouth Skimmers, 3 Returns
    Equip 3.0 HP Pentair VS pump motor, 48 FNS Plus DE filter, IC20 SWCG, 400Btu NG Heater
    Extras Easy Touch Automation, Pentair LED Lite, Kreepy Krawl Racer pressure cleaner
    Water pH 7.5, Total Alk 90, Free Cl 4.5, Combine Cl 0.25, CYA 65, CH 275, Salt 4100ppm, Borates (Boric Acid) 50ppm

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    Richard320's Avatar
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    Re: How to gauge proper START/CLEAN DE Filter settings with a variable speed pump?

    Just pick a setting and use that as your baseline. Then when it goes up 25%, backwash. High speed will show the higher pressure, which will make it easier to see 25% rise. Only use the start pointer, ignore the higher one.

    I have a single speed pump. Because of all the vagaries of flow curves and head loss and all that stuff, I get different clean pressure readings whether I'm on pool in-pool out, pool in-blend out, blend in-blend out, or spa in-spa out. So I take my baseline reading in the usual position. In my particular case, that's 16psi. That's where that ring sits. It's just a reminder. I can see the flow reducing when it gets near 20. If I waited for it to go all the way until that gauge ring said it was time at 26 psi, I'd have no flow!
    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
    Troublefree does not mean Maintenancefree. It's like brushing your teeth: You can spend a couple minutes a day and pennies a week or go to the dentist once a year and spend several thousand dollars.
    A pool is like a pet - you have to feed it every day, even the days you don't want to play with it!

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    Mod Squad pooldv's Avatar
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    Re: How to gauge proper START/CLEAN DE Filter settings with a variable speed pump?

    Yep, use 3100 as your default "check the filter pressure speed". When it goes up 20-25% from there clean it.
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    Re: How to gauge proper START/CLEAN DE Filter settings with a variable speed pump?

    Ok I think I got it....Thanks Richard!

    so basically, what I should do is:

    1-Capture the baseline PSI of each of my commonly used Speed Settings, and just use that as my starting point
    2-If any of these starting points increase pressure in the 25% range, I should just backwash

    Do I have that correct?.....I guess its safe to assume, that if any of my speed settings increase by 25%, they should all increase by 25% equally if its dirty filter in need of backwashing...correct?

    I shouldnt expect 1 setting to be increasing by 25% while the others are fine otherwise that could be an entirely different issue?
    Design 14x26 (10,000 gal) in ground vinyl pool, 2 Wide Mouth Skimmers, 3 Returns
    Equip 3.0 HP Pentair VS pump motor, 48 FNS Plus DE filter, IC20 SWCG, 400Btu NG Heater
    Extras Easy Touch Automation, Pentair LED Lite, Kreepy Krawl Racer pressure cleaner
    Water pH 7.5, Total Alk 90, Free Cl 4.5, Combine Cl 0.25, CYA 65, CH 275, Salt 4100ppm, Borates (Boric Acid) 50ppm

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    Richard320's Avatar
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    Re: How to gauge proper START/CLEAN DE Filter settings with a variable speed pump?

    I would just use the high speed baseline. There's only one pointer on that reminder ring.
    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
    Troublefree does not mean Maintenancefree. It's like brushing your teeth: You can spend a couple minutes a day and pennies a week or go to the dentist once a year and spend several thousand dollars.
    A pool is like a pet - you have to feed it every day, even the days you don't want to play with it!

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