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Thread: Reducing overall pressure

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    Reducing overall pressure

    Other than changing to a variable or 2 speed pump, what are some ways to lower the pressure on my system? I had two ideas. 1. Use larger openings for the returns. 2. A return loop from the output to the input of the pump with a valve - although I'm not sure how much that would actually help. Any other ideas? Once this pump is done, I'm definitely getting a variable speed.
    25' x 13' Roman, 12000 gal IGP, Plaster, with 500 gal Spa
    SWG, 1 HP Max Flo Pump, C-900 cartridge filter
    Solar heat

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    mas985's Avatar
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    Re: Reducing overall pressure

    Why do you care about 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: Reducing overall pressure

    The lower the pressure, the longer my solar panels will live.
    25' x 13' Roman, 12000 gal IGP, Plaster, with 500 gal Spa
    SWG, 1 HP Max Flo Pump, C-900 cartridge filter
    Solar heat

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    mas985's Avatar
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    Re: Reducing overall pressure

    Where are the panels installed and how high are they relative to the pump?

    What type of panels do you have?

    What is the filter pressure now with the panels engaged?

    Are you now bypassing any water around the panels?

    Have you actually measured the pressure right at the panels?


    Personally, I think the whole panel pressure concern is a little overblown. Lower might be better but sometimes, there is nothing you can do.
    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: Reducing overall pressure

    I have measured 4-5 psi up at the panels at the lower header. Talking to a rep at the company, I was told the lower the pressure, the longer life I can expect.

    But back to the question.... will a return loop lower pressure enough to make it worth plumbing?
    25' x 13' Roman, 12000 gal IGP, Plaster, with 500 gal Spa
    SWG, 1 HP Max Flo Pump, C-900 cartridge filter
    Solar heat

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    mas985's Avatar
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    Re: Reducing overall pressure

    So you didn't really answer most of my questions. It can make a difference where the panels are installed.

    Where are the panels installed and how high are they relative to the pump?

    What type of panels do you have?

    What is the filter pressure now with the panels engaged and bypassed?

    Are you now bypassing any water around the panels?
    Also, do you have a solar valve?


    But 4-5 PSI is not much and lowering could cause problems with priming. I really don't think it would be a good idea.
    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: Reducing overall pressure

    OK. Panels are Solar Bear, about 15 ft average above the pump on the roof. Very close to the pump, so minimal pipe run.
    Yes, I have recently installed a solar valve with the check valve built in, so the panels drain properly.

    If you don't think pressure is important in the life of the panel, then what? Installation?
    25' x 13' Roman, 12000 gal IGP, Plaster, with 500 gal Spa
    SWG, 1 HP Max Flo Pump, C-900 cartridge filter
    Solar heat

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    mas985's Avatar
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    Re: Reducing overall pressure

    UV exposure is probably the most important factor and of course, you can't avoid that. Pressure would become important if it was really high. Installation can be an issue if the panels move around in the wind.

    Last two questions?

    What is the filter pressure now with the panels engaged and bypassed?

    Are you now bypassing any water around the panels?
    With the solar valve, you can bypass water around the panels to reduce the pressure but only so much.
    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: Reducing overall pressure

    Filter pressure, solar bypass ~ 10 psi
    Filter pressure, solar 100% ~ 18 psi
    I have the solar valve set so filter pressure reads 14 psi, so some portion is bypassed.

    From what the manufacturer has told me, pressure is very important. I also think the cycling of panels, on and off, causing them to expand and contract, does harm, especially if it is rubbing on asphalt shingles.
    25' x 13' Roman, 12000 gal IGP, Plaster, with 500 gal Spa
    SWG, 1 HP Max Flo Pump, C-900 cartridge filter
    Solar heat

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    mas985's Avatar
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    Re: Reducing overall pressure

    Ok, so if you were to adjust the solar valve to reduce the rise from 14 PSI to 12 PSI (or an increase of 2 PSI from no panels), the panel pressure should drop by a bit more than 2 PSI. Although I still think 4 PSI should be low enough for any panel even if they are very delicate. I have run mine for 10 years at PSI rises much much higher than that without any issues.
    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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