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Thread: RPM's and GPM's - Dual Pump

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    RPM's and GPM's - Dual Pump


    I think it has actually come down to me ordering a dual speed 2hp Whisperflo pump. I want to see if anyone can confirm the following for me though. Pulling postings with GPM's from many people I have concluded the following:
    based on my usage, I am approximating the following GPM's needed for:
    solar 7 4x16panels, 30ft up on roof.....30-40GPM
    jets in step-n-spa (NOT a separate spa) 3 jets 45gpm
    regular filtering of pool 33gpm/10hour turnover rate (19,600gallons)
    Pentair QuadDE80 filter (??gpm, but I am sure it will fit into the scheme of things)

    My question is the dual speeds operate at 1750 RPM for low and 3450RPM for high does anyone know the GPM's for these speeds?

    I know KTDave had provided the following information regarding his VS3050 pump, but not sure if the RPM and GPM apply the same for a dual speed pump. If this compares apples to oranges, can someone provide to me with estimated GPM ofr the two speeds on a dual pump.....please.

    To me, it does not seem the VS3050 would be worth the extra money since all of my applications need to operate at the about the same RPM. If this is the case, I also feel I would not need an automatic control unit either.

    Thanks again!

    KTDave provided the following:

    The lowest reading on the flow meter is 15 GPM (highest is 70).

    RPM - GPM
    1370 - 15
    1500 - 24 (default speed 2)
    1600 - 28
    1700 - 33
    1800 - 37
    1900 - 41
    2000 - 46
    2300 - 57
    2350 - 60 (default speed 3)
    2500 - 65
    18x36 IG Vinyl Grecian Lazy L (20k gallons) ~ Whisperflo DS 2.0HP pump ~ QuadDE100 filter ~ Autopilot SWG DIG-60 ~ (7) 4x16 solar panels

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    mas985's Avatar
    Join Date
    May 2007
    Pleasanton, CA
    The numbers that KTDave posted will probably not apply to your pool. They are dependent on the plumbing which is unlikely to be the same between the two pools. In additon, the two speed 2 HP Whisperflo will have a different head curve so it is very difficult to compare the pumps.

    Also, as a good guess, a two speed pump on low speed will pump about 1/2 the GPM of high speed. However, you need to know the flow rate at high speed to use this approximation. However, it is unlikely that you will be able to run a two speed on low with the solar and a 30' roof. The Intelliflo will allow you to set the flow rate such that the panels remain primed and the valcuum release valve closed.

    There are ways to estimate what a two speed pump would do on a specific plumbing system but you need to estimate what your current head loss is for the pool. I can help but I would need some more information:

    Current pump model
    Current filter PSI
    Plumbing description: Number (pool to pad) and length of runs for both suction and return side as well as pipe size
    Hydraulics 101; Pump Ed 101; Pump/Pool Spreadsheets; Pump Run Time Study; DIY Acid Dosing; DIY Cover Roller
    18'x36' 20k plaster, MaxFlo SP2303VSP, Aqualogic PS8 SWCG, 420 sq-ft Cartridge, Solar, 6 jet spa, 1 HP jet pump, 400k BTU NG Heater

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    JasonLion's Avatar
    Join Date
    May 2007
    Silver Spring, MD
    I suspect you would be fine with a much smaller pump. It sounds like the peak GPM required is under 50. Even the 3/4 HP WhisperFlo can pump 50 GPM on full speed in most pools, though it can vary rather dramatically depending on the details of your plumbing.
    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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    mas985 - I do not have the numbers you need b/c my pool has yet to be installed. Install start date is either 4/21 or 4/28. Thanks for offering to help me and calculate those numbers though!!

    I do understand that the solar will need to operate somewhere btwn the low and high on a dual, so perhaps it makes sense to go with the 4x160 and and Easytouch setup with Intellichlor IC40.

    I realize that the 4x160 only allows 4 speeds to be programmed, which I feel is sufficient in my case. Speeds 1-4 can be for filter, jets, solar and vacuum. I can get up and turn the dial for whatever else I might need.

    I was going to go with the Aqualogic panel and SWG a few weeks ago, but the Intellichlor sounds like a better fit and the Eassytouch will work much better too since all other equipment is Pentair too.

    Does anyone know if the solar side of the Easytouch is easy to install and program? If you remember from a post last week, my solar installer was having a meltdown that I was switching controls on him. Not sure I will inform him of my switch from an Aqualogic to an ET until he shows up.

    Does this setup sound good and efficient?
    18x36 IG Vinyl Grecian Lazy L (20k gallons) ~ Whisperflo DS 2.0HP pump ~ QuadDE100 filter ~ Autopilot SWG DIG-60 ~ (7) 4x16 solar panels

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