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Thread: Low speed enough to run SWG?

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    Low speed enough to run SWG?

    I'm looking at replacing my current 1 speed pump with this 2 speed: A.O. Smith 1 H.P Square Flange Dual Speed Up Rate Motor - UQS1102R - INYOPools.com


    My concern is having enough power at the low speed setting (1/6 hp) to run my SWG. The requirement is a minimum of 20 GPM. My equipment pad is less that five feet above the height of the water. Is there an easy way to figure out whether this pump would be sufficient?
    33K gal L-shaped (2008) IG vinyl | AutoPilot Digital SC60 SWG | 1 HP Sta-Rite Dura-Glass pump (model P2RA5E-181L) | 300 sqft Sta-Rite cartridge filter (model S7M120) | Dolphin Sprite cleaning robot | Merlin Smart Mesh winter cover

    South-Central PA

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    Mod Squad JVTrain's Avatar
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    Re: Low speed enough to run SWG?

    This would depend on the amount of head (or resistance) in your current plumbing configuration. If you look at this performance curve, your motor would be the B and G curves, assuming that the Pentair 1 HP, 230V, 2-speed Whisperflo that uses this same motor is equivalent.



    I'm not sure of a good way to determine your feet of head directly... but as long as you had less than ~20 feet of head in the system, it would be over 20 gpm at low speed, unless I am mistaken.
    Joel - TFP Moderator - Minnesota - **Become a TFP Supporter!** Helpful Links: ABCs of Pool Water Chemistry - SLAM Procedure - Chlorine/CYA Chart
    40x20 Pool: 32K Gallons * Vinyl * Bleach Chlorination * Hayward S270T Sand Filter * Pentair SuperFlo 1 HP * Teledyne/Laars Heater * AquaVac Tigershark * TF-100 w/ SpeedStir
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    mas985's Avatar
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    Re: Low speed enough to run SWG?

    It should not be an issue unless you have a lot of head loss in the plumbing. What was the clean filter pressure?
    Mark
    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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    Re: Low speed enough to run SWG?

    Quote Originally Posted by JVTrain View Post
    I'm not sure of a good way to determine your feet of head directly... but as long as you had less than ~20 feet of head in the system, it would be over 20 gpm at low speed, unless I am mistaken.
    JVTrain, I have tried to read/understand the process of determining feet of head, but am still confused. How is this determined?

    Quote Originally Posted by mas985 View Post
    It should not be an issue unless you have a lot of head loss in the plumbing. What was the clean filter pressure?
    mas985, my normal clean pressure is around 11 psi.
    33K gal L-shaped (2008) IG vinyl | AutoPilot Digital SC60 SWG | 1 HP Sta-Rite Dura-Glass pump (model P2RA5E-181L) | 300 sqft Sta-Rite cartridge filter (model S7M120) | Dolphin Sprite cleaning robot | Merlin Smart Mesh winter cover

    South-Central PA

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    mas985's Avatar
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    Re: Low speed enough to run SWG?

    It doesn't seem like your plumbing is overly restrictive so it shouldn't be a problem.

    As for determining head loss, there are a couple different methods I use and I have a couple tools in my signature that helps with that but I don't think you need to go to the trouble. 20 GPM on the above head curves is very restrictive and I don't think I have seen a pool yet with that restrictive of plumbing.
    Mark
    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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