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Thread: "slow" or undersized pool pump

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    Diver's Avatar
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    "slow" or undersized pool pump

    I have a 30k gallon inground pool with Hayward 1HP superpump. With a big help from Mark (mas985) the flow rate was estimated at 67-71 GPM, which gives me a 7-8 hour turnover time.

    I was thinking about what kind pump to get in case I need to replace my current one. I have no water features, no spa, no solar heater, nor I run manual vacuum. In other words my pump is only for filtering and water circulation.

    I would want my new pump to be efficient and cost effective. I know that 2 speed pumps have a lower speed and pumping twice as slow saves 4 times the energy. I don’t really want a 2 speed pump, or variable speed pump, since in my simple thinking I only need a slow speed mode and don’t want to pay for option of having higher speed(s) that I don’t need.

    So is there such a thing as a “slow” pump? Or can the same effect be achieved by undersizing the pump and running maybe 1/2HP pump for twice as long for my size of the pool?
    26K In-ground Vinyl Pool | Hayward DE4820/SP0710XR50 filter | 1.125 HP Dual Speed Hayward Super Pump | Aquasol Solar

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    Mod Squad Bama Rambler's Avatar
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    Re: "slow" or undersized pool pump

    The problem in your logic is that you're not taking to account that you need a larger pump to effectively backwash your DE filter and if you have a vacuum you may need to run the pump on high for that. I'd personally go back with a 1hp 2-speed pump. That way you get the best of both worlds.

    Like I told my dad once about getting an A/C in his new car. You don't have to use it if you don't want to, but if you ever want to, you can't if you don't have it.
    Dave J. TFP Moderator
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    mas985's Avatar
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    Re: "slow" or undersized pool pump

    You already have one of the slowest/smallest/most efficient single speed pumps on the market. So as long as there is nothing wrong with the pump, why replace it? The SuperPump 1 HP is an uprated pump and is actually smaller than the Whisperflo 1/2 HP WFE-2.
    Mark
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    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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    Diver's Avatar
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    Re: "slow" or undersized pool pump

    Mark,

    I'm not replacing it i was thinking if for some reason i have a pump failure and need to replace it quick then i want to know which one to get up front. I don't want to spend a day or two doing the research on pumps while my pool is turning into a swamp while my pump is down.

    From what you're saying it sounds like what i have is perfect for my situation and i would simple get the same pump if i need to. Would it make sense to consider 3/4 HP superpump or will it be too small for my pool? Would running it 33% longer be the same as running 1HP?
    26K In-ground Vinyl Pool | Hayward DE4820/SP0710XR50 filter | 1.125 HP Dual Speed Hayward Super Pump | Aquasol Solar

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    mas985's Avatar
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    Re: "slow" or undersized pool pump

    If you were to eventually replace the pump, I would go with the 1 HP SuperPump two speed version over the 3/4 HP single speed. That way you have enough flow if you need it for backwashing and you can run it on low speed most of the time to save much more money than the single speed would.
    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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    Diver's Avatar
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    Re: "slow" or undersized pool pump

    perfect! that's the answer i was looking for.
    26K In-ground Vinyl Pool | Hayward DE4820/SP0710XR50 filter | 1.125 HP Dual Speed Hayward Super Pump | Aquasol Solar

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    Diver's Avatar
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    Re: "slow" or undersized pool pump

    Mark, is there 115V equivalent of 1HP 2 speed 1-1/2" piping superpump? Pentair Wisperflow (WFDS24?) seems to be 115V, but as far as i can see, it's for 2" piping..
    26K In-ground Vinyl Pool | Hayward DE4820/SP0710XR50 filter | 1.125 HP Dual Speed Hayward Super Pump | Aquasol Solar

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    JasonLion's Avatar
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    Re: "slow" or undersized pool pump

    The WFDS24 is fine with 1.5" pipes, you just need to use adapters when plumbing it in.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
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    mas985's Avatar
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    Re: "slow" or undersized pool pump

    Just keep in mind that the WFDS24 is much stronger/larger pump than the SuperPump and will use more energy. Even the Whisperflo 1/2 HP (WFE-2) is a larger pump than the SuperPump 1 HP. Odd but true. One of the reasons why you can't rely upon pump HP labels for sizing.
    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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    Diver's Avatar
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    Re: "slow" or undersized pool pump

    Mark,

    Your speadsheet backs up your statement - it seems to be all about SF. Even though WFDS24 is larger pump, at slow speed for WFDS24 i should see about 50% reduction in operating cost as compared with regular 1HP superpump.

    i'll keep going thru your data in the xls -there is a lot of useful info there. thank you for putting it all together.

    edit: looking at the Scenario1 in the xls, it seems that you have 1 average turnover per day for full speed and 0.75 for slow speed. is there some reason that the slow speed has lower turnover number?
    26K In-ground Vinyl Pool | Hayward DE4820/SP0710XR50 filter | 1.125 HP Dual Speed Hayward Super Pump | Aquasol Solar

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    mas985's Avatar
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    Re: "slow" or undersized pool pump

    Many people who use both VS and 2 speed pumps find that they need to run at high speed at least a portion of the run cycle for things such as suction cleaners, skimming and even solar systems. I run my two speed at high speed for at least 2 hours per day and more if solar is engaged just for the cleaner and for better skimming.
    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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    Diver's Avatar
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    Re: "slow" or undersized pool pump

    115V & 2 speed requirement + price narrowed the list significantly. I arrived at 3 pumps and after i skipped the one with 2" fittings and being more pricey then the others, i'm left with two:

    Pentair SuperFlow 3/4 HP &
    Pentair Sta-Rite SuperMax 3/4 HP.

    They both are the same price ($284.94 & $284.84 @ http://www.swimnsaveusa.com) and seem that they are pretty much identical. As a matter of fact, i don't really see what is different about them. Is one better then another?

    It seems that the data for this pumps are not complete in the xls

    edit: prices were for single speed pump - my bad.
    26K In-ground Vinyl Pool | Hayward DE4820/SP0710XR50 filter | 1.125 HP Dual Speed Hayward Super Pump | Aquasol Solar

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    Re: "slow" or undersized pool pump

    The SuperMax is a rebadged SuperFlo so they are identical pumps except for the color.
    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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    Diver's Avatar
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    Re: "slow" or undersized pool pump

    that explains it! i think i will settle for superflo as a possible replacement in the future if need arises. thank you for you help!
    26K In-ground Vinyl Pool | Hayward DE4820/SP0710XR50 filter | 1.125 HP Dual Speed Hayward Super Pump | Aquasol Solar

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    Green1340's Avatar
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    Re: "slow" or undersized pool pump

    Diver,

    You might wanna look at a1poolparts.com for your pump. That particular pump is a few $$$ cheaper there and they also have an energy efficient model for a few $$$ more.

    Greenhaw
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