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Thread: New to trouble free pool - gpm question

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    New to trouble free pool - gpm question

    So far so good! My wife and I have been rehabbing an old patio pool that came with house. We have been updating a bit each year. 4 th summer This year we put in a 115 volt vs pump. I wanted a timer and it just made sense to put in a vs. next year I will probably put a flow guage in. My swg will not run at less than 20 gpm. I get this flow at about 1750 rpm. Is there a way to figure out what rpm would be for 40 gpm? I would not think that it is linear...... But maybe. If that was the case 40 gpm would be 3500 rpm. Thoughts? Pictures soon.
    10,800 gallon swg, old big btu gas heater, solar cover, 1.5 hp 115 volt vs pump, sand filter, vinyl in ground

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    mas985's Avatar
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    Re: New to trouble free pool - gpm question

    First, which VS pump did you get?

    Next, how is the SWG plumbed? Some have a bypass.

    So is 1750 RPM where the SWG just started to generate CL?

    What is the filter pressure at full speed?


    1750 seems very high for 20 GPM.
    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: New to trouble free pool - gpm question

    Thanks for response! Pentair superflo vs. swg does not have a bypass and is after the sand filter. Swg just starts at about 1750. Psi at 1750 is about 8 and at 2500 about 15. I have not check at highest speed. I agree 1750 seems high for 20 gpm
    10,800 gallon swg, old big btu gas heater, solar cover, 1.5 hp 115 volt vs pump, sand filter, vinyl in ground

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    mas985's Avatar
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    Re: New to trouble free pool - gpm question

    Head loss seems very high based upon the pressure and RPM. What was your old pump model and 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: New to trouble free pool - gpm question

    Old pump was a 1hp marlow and psi was about 18 psi. Old pool store thought 1/2 hp would be plenty.
    10,800 gallon swg, old big btu gas heater, solar cover, 1.5 hp 115 volt vs pump, sand filter, vinyl in ground

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    mas985's Avatar
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    Re: New to trouble free pool - gpm question

    Sounds like your plumbing just has really high head loss. What size is your sand filter and the pipe? How long are the runs to the pool? It could be your old heater.
    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: New to trouble free pool - gpm question

    I will get some pictures up in the next few days. It is a CRAZY plumbing job for sure with lots of right angles. Runs to the pool are not too long. I will attempt to measure tonight. thank you.

    QQQ
    10,800 gallon swg, old big btu gas heater, solar cover, 1.5 hp 115 volt vs pump, sand filter, vinyl in ground

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