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Thread: Too much HP?

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    Too much HP?

    I am in the process of an extensive rebuilt of my pool. It is 16x32 20k gallon vinyl liner inground. Waterfall is on a seperate pump so I will exclude any of that info here.

    In the discussion with PB we agreed a 3/4 to 1 HP 2-speed pump is what was going to be used. That info I got here on this forum. Anyway he used a 1.5hp with a service factor of 1.6 for total HP of 2.4HP.

    My lines are as follows; [2] main drains attached to one [2"] line traveling about 50 foot to pump, [1] skimmer line also 2" running about 40 foot. I also have [2] 2" returns running 15' and 40'.

    Running on low speed a get pressure reading of about 4 psi at the filter. Flow seems just as good as my old set-up [1 hp pump with 1.5 line]. High however runs much higher [28 psi] and seems loud. My old set-up ran at about 10 psi.

    I am sure it is relavent so here is my equipment. I have AquaCal heatpump and and autopilot SWG. The filter is a Hayward 48?? DE filter.

    Is this too high of HP? Is it bad other than using too much energy? Can I change the pumps HP to lower when motor goes in 10 or so years? Should I ask the PB for a different pump?

    Thought or advice appricated.

    Thanks
    Daren
    DRB
    16x32 20K IG vinyl, Hayward Pro Grid DE4820 w/ 2-speed 1.5HP Hayward TriStar pump with a .75HP impeller installed, AutoPilot Digg-220

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    mas985's Avatar
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    Re: Too much HP?

    Yes, the pump will use more power than a 3/4 HP on both high and low speeds. The pressure is a little high indicating the pump is too large for the plumbing. If you had agreed with PB that a smaller pump was better, why did he put in such a large pump? I would get him to swap out the pump to what you had agreed.

    If that becomes an issue, then one cheap and quick fix is to downsize the impeller. The existing motor will work fine with that and it will use about the same energy as a regular 3/4 HP 2 speed. But I would get him to do what he had agreed to.
    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: Too much HP?

    Yes I want him to swap out to a smaller pump.

    Can running that higher rated pump cause damage to the lines or filter?

    Thanks
    Daren
    DRB
    16x32 20K IG vinyl, Hayward Pro Grid DE4820 w/ 2-speed 1.5HP Hayward TriStar pump with a .75HP impeller installed, AutoPilot Digg-220

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    mas985's Avatar
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    Re: Too much HP?

    48 sq-ft filter would have a max flow rate around 96 GPM but since your filter pressure is so high, it is unlikely the pump is producing much in the way of flow rate. So you are just wasting energy. BTW, which 1.5 HP pump did he install (make/model)?
    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: Too much HP?

    Hayward 2 -speed TriStar
    DRB
    16x32 20K IG vinyl, Hayward Pro Grid DE4820 w/ 2-speed 1.5HP Hayward TriStar pump with a .75HP impeller installed, AutoPilot Digg-220

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    mas985's Avatar
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    Re: Too much HP?

    Was that an up rated or full rated pump? Either a SP3210X152 or a SP32152EE. The former is a 1.5 HP up rated pump which is the same as a 1 HP full rated.
    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: Too much HP?

    My guess is full rated? Pump has a sticker as 1.5 hp, 1.6 SF and 2.4THP
    DRB
    16x32 20K IG vinyl, Hayward Pro Grid DE4820 w/ 2-speed 1.5HP Hayward TriStar pump with a .75HP impeller installed, AutoPilot Digg-220

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    mas985's Avatar
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    Re: Too much HP?

    Makes sense given the filter pressure. The flow rate is probably less than 80 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: Too much HP?

    I don' think it would but would lower hp = higher flow rate?

    Do I want as high as a flow rate as possible?

    My PB is out of town for a while but will have whoever closes the pool look at it.

    Thanks
    Daren
    DRB
    16x32 20K IG vinyl, Hayward Pro Grid DE4820 w/ 2-speed 1.5HP Hayward TriStar pump with a .75HP impeller installed, AutoPilot Digg-220

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    mas985's Avatar
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    Re: Too much HP?

    No and No. Lower HP usually results in lower flow rates which costs less in energy and tends to work better for filters.
    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: Too much HP?

    Safety cover is in and PB is closing the pool today. I switched the pump to high speed and see that the PSI fell to about 18. Is this a good reading?

    I think I still like to go to lower the HP pump but I need to make sure I have a good enough flow rate for Autopilot SWG [15 gpm, I think manual said] and the AquaCal Heat Pump [ I believe the manual mention between 30 and 75 gpm]

    How would I go about checking my flow rate? Is there a meter that wouldn't involve cutting any lines that I can use?

    Thanks for any advice.

    Daren
    DRB
    16x32 20K IG vinyl, Hayward Pro Grid DE4820 w/ 2-speed 1.5HP Hayward TriStar pump with a .75HP impeller installed, AutoPilot Digg-220

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    mas985's Avatar
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    Re: Too much HP?

    You can use a flow meter but they are fairly expensive and most are not all that accurate. TFP test kits sells one that can be installed in a check valve that is a bit more accurate.

    However, I can usually estimate flow rate just as accurately with the filter pressure and a description of the suction side plumbing which you have done. I only need to know the pad size plumbing, the backwash valve size and the height of the pump relative to the water level.

    You can also download the same spreadsheet that I use in my signature if you are interested.
    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: Too much HP?

    By pad size plumbing do you mean pump outlets? If so they are all 2", including backwash valve.

    Height of pump is maybe 1' above water level. It's an I ground pool and the pump sets on the concrete pool deck. As I mentioned psi has dropped to about 18. That is with media (de) but clean. All vacuuming has been done with robot.
    Thanks
    Daren
    DRB
    16x32 20K IG vinyl, Hayward Pro Grid DE4820 w/ 2-speed 1.5HP Hayward TriStar pump with a .75HP impeller installed, AutoPilot Digg-220

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    mas985's Avatar
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    Re: Too much HP?

    So my estimate for flow rate is around 106 GPM which is a little higher than the maximum flow rate of the filter so that is not ideal. It could reduce filter capabilities or worst case, damage the grids in some way. In the short term, one thing you could do is throttle the flow rate if you have a valve somewhere after the filter. Once you hit 22 PSI, the flow rate should drop below 96 GPM which still isn't ideal.

    Really, you should get the PB to change out the pump to what you had agreed to and preferably the 3/4 HP pump if it is going to be TriStar.
    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: Too much HP?

    I think low speed is 1/2 the rpm's as high, so would that give me a flow rate of 53 GPM? The psi on low was around 4. By all means I will try to get the PB to swap pumps.

    The one thing I really care about is having enough flow for the SWG and heat pump to operate on low speed.

    Again thanks
    Daren
    DRB
    16x32 20K IG vinyl, Hayward Pro Grid DE4820 w/ 2-speed 1.5HP Hayward TriStar pump with a .75HP impeller installed, AutoPilot Digg-220

  16. Back To Top    #16
    mas985's Avatar
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    Re: Too much HP?

    Yes, low speed of a two speed pump is around 1/2 of high speed.
    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: Too much HP?

    I see Tri-star does not have a 2-speed 3/4 HP pump. Would the 1HP Tri-star be a viable option?

    If that becomes an issue, then one cheap and quick fix is to downsize the impeller. The existing motor will work fine with that and it will use about the same energy as a regular 3/4 HP 2 speed.
    Or would it be better to downsize the propeller? If so which one would I have the PB order?

    The PB should be here within 2 weeks, He I good guy and said he won't argue about a pump but I have a feeling he may get upset about me questiong his work based on my internet research.

    While saving energy is high on list, the most important thing is all runs well. Which means enough flow on low speed for the SWCG to work, and not too much so that the heat pump doesn't work efficently.

    Again thanks for all the help.
    Daren
    DRB
    16x32 20K IG vinyl, Hayward Pro Grid DE4820 w/ 2-speed 1.5HP Hayward TriStar pump with a .75HP impeller installed, AutoPilot Digg-220

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    Re: Too much HP?

    Another quick question. Based on your previous projection of flow rate:

    So my estimate for flow rate is around 106 GPM which is a little higher than the maximum flow rate of the filter so that is not ideal. It could reduce filter capabilities or worst case, damage the grids in some way.
    ON low speed and getting a PSI reading of 4, what is the flow rate?

    Thanks
    Daren
    DRB
    16x32 20K IG vinyl, Hayward Pro Grid DE4820 w/ 2-speed 1.5HP Hayward TriStar pump with a .75HP impeller installed, AutoPilot Digg-220

  19. Back To Top    #19
    mas985's Avatar
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    Re: Too much HP?

    Low speed is always about 1/2 of high speed so that would be about 53 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

  20. Back To Top    #20

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    Re: Too much HP?

    [quote][/I see Tri-star does not have a 2-speed 3/4 HP pump. Would the 1HP Tri-star be a viable option?

    Quote:
    If that becomes an issue, then one cheap and quick fix is to downsize the impeller. The existing motor will work fine with that and it will use about the same energy as a regular 3/4 HP 2 speed.


    Or would it be better to downsize the propeller? If so which one would I have the PB order?

    The PB should be here within 2 weeks, He I good guy and said he won't argue about a pump but I have a feeling he may get upset about me questiong his work based on my internet research.

    While saving energy is high on list, the most important thing is all runs well. Which means enough flow on low speed for the SWCG to work, and not too much so that the heat pump doesn't work efficently.

    Again thanks for all the help.
    Daren
    DRB
    16x32 20K IG vinyl, Hayward Pro Grid DE4820 w/ 2-speed 1.5HP Hayward TriStar pump with a .75HP impeller installed, AutoPilot Digg-220

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