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Thread: Suggestions on pump speed?

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    Suggestions on pump speed?

    I want to use the least amount of energy to use the solar heat for the entire day.

    I have a brand new Intelliflo VS hooked up to a Zodiac iAqualink.
    The solar is split into two levels, the peak of the top level is about 30 feet off of the water, while the peak of the lower level is about 20 feet off of the water.
    My filter was just cleaned and is currently reading about 10psi at low pump speeds.

    At 1550 RPM with the solar engaged, I donít feel any water coming out. The Jandy AquaPure does report ďFlowĒ, however (even after several minutes of me not feeling water going into the pool.)
    At 1650 RPM with the solar engaged, I feel water moving, but you can hear some air in the system. I donít see bubbles going into the pool, though.
    At 2200 RPM with the solar engaged, I donít hear any air.

    Some questions:
    1) Is it possible that at 1650 RPM that only the lower solar element is active, and the coils on the 2nd story roof are dry? If so, is there a way for me to know that the entire solar array has flowing water?

    2) If the pump isnít turning fast enough, can I destroy something in the AquaPure by running it when thereís no real flow of water? I would think that the AquaPure flow sensor would sense the lack of flow, but might this be fooled by a pump thatís kinda churning water without actually getting any real flow?

    Iím also generally interested in recommended speeds when other devices are on.
    For instance, when the gas heater is running, do I need to increase the pump speed so that the water doesnít superheat?

    Hereís what I currently have for speeds:

    Solar Heat: 1900 (runs 9:30am to 6:30pm)
    Pool: 1500 (only runs if solar panels arenít hot enough)
    Cleaner: 2850 (runs 1.5 hours twice a day) (In floor jets run off of separate single speed pump)
    Pool Heat: 3000 (rarely used)
    Spa Heat: 3000

    Does this seem like a reasonable setup?

    Is there any benefit to bumping up the pump to 3300 RPM a couple times a day to try to unstick any crud somewhere, or is that pointless?

    Here's some data on RPM vs. Power for the pump.

    solar off solar on
    RPM Watts RPM Watts
    1500 235
    1800 389 1800 359
    1900 454 1900 420
    2000 482
    2100 551

    2750 1183
    2850 1316
    3000 1595

    thanks,
    Derek
    saltwater AquaPure freeform pool from 2009. Now controlled via Aqualink.

  2. Back To Top    #2
    mas985's Avatar
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    Re: Suggestions on pump speed?

    There needs to be at least 15 PSI filter pressure (maybe more) to keep the vacuum release valve closed on the roof and you probably will need higher RPM to do that so 2200 RPM sounds about right.

    As for ideal speeds, the most efficient speed is around 1000 RPM but the pump may not have enough flow rate for anything but filtering and chlorination. Everything else is going to be trial and error.
    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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    Mod Squad jblizzle's Avatar
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    Re: Suggestions on pump speed?

    Also, note that the most efficient heating of the pool is done with as high of flow rates/pressures your panels can handle ... this is likely a much higher RPM. But if you do not care about how well the pool heats up, then lower RPM will certainly save you money.
    Jason, TFP Moderator
    18k IG pebblesheen pool, Hayward ProLogic P4 w/ T-15 SWG, Pentair 1HP 2-speed Superflo, Hayward 6020 DE filter
    500 sqft Heliocol solar panels, ThePoolCleaner, TF-100 test kit w/ SpeedStir
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    Re: Suggestions on pump speed?

    I do care about how well the pool heats up, but I thought that flow rate had little to do with the heat transfer.
    I thought if I had 3 times the flow, the water would heat up one third as much on its way through for an equal amount of heat added to the pool. Is that not true?
    saltwater AquaPure freeform pool from 2009. Now controlled via Aqualink.

  5. Back To Top    #5

    Re: Suggestions on pump speed?

    Quote Originally Posted by mas985
    There needs to be at least 15 PSI filter pressure (maybe more) to keep the vacuum release valve closed on the roof and you probably will need higher RPM to do that so 2200 RPM sounds about right.

    As for ideal speeds, the most efficient speed is around 1000 RPM but the pump may not have enough flow rate for anything but filtering and chlorination. Everything else is going to be trial and error.
    Thanks Mas,
    What happens if the release valve does not stay closed? I get air in the system? but then I'd see air bubbles coming out of the output jets, right?
    saltwater AquaPure freeform pool from 2009. Now controlled via Aqualink.

  6. Back To Top    #6
    Mod Squad jblizzle's Avatar
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    Re: Suggestions on pump speed?

    Quote Originally Posted by derekt75
    I do care about how well the pool heats up, but I thought that flow rate had little to do with the heat transfer.
    I thought if I had 3 times the flow, the water would heat up one third as much on its way through for an equal amount of heat added to the pool. Is that not true?
    Absolutely not true. The higher the flow rate the better. Although the temperature difference will certainly be lower across the solar panels ... you are moving more water at that lower delta T which ends up adding more heat to the pool.

    Lots of good info here if you look near the middle of the first page (read after linen first comments and then Jason's explanation):
    solar-heater-performance-t50022.html?hilit=solar%20efficiency
    Jason, TFP Moderator
    18k IG pebblesheen pool, Hayward ProLogic P4 w/ T-15 SWG, Pentair 1HP 2-speed Superflo, Hayward 6020 DE filter
    500 sqft Heliocol solar panels, ThePoolCleaner, TF-100 test kit w/ SpeedStir
    Pool School + Test Kit + PoolMath = A TROUBLE FREE POOL
    If you found TFP helpful and we saved you money ... Become a TFP Supporter!

  7. Back To Top    #7
    mas985's Avatar
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    Re: Suggestions on pump speed?

    Quote Originally Posted by derekt75
    What happens if the release valve does not stay closed? I get air in the system? but then I'd see air bubbles coming out of the output jets, right?
    Right!
    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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