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Thread: Questions for Mark

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    kevreh's Avatar
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    Questions for Mark

    Hi Mark;

    I saw your specs in your signature as;

    "18'x36' 20k gallon plaster/gunite pool, 1/2 HP 2sp pump, Aqualogic PS8 SWCG, 420 sq-ft Cartridge Filter, 450 sq-ft EPDM Solar Panel, 6 jet spa, 1 HP jet pump, 400k BTU NG Heater"


    That gave me pause as a 1/2 HP pump for a 20k pool AND filter AND Solar Panel (on the 2nd story, mentioned in a thread) seemed very underpowered. I currently have a system somewhat similar to yours (specs below) and am considering a 2 speed pump, downgraded to 3/4HP. I have a 1HP Superpump now and am wondering if I should replace it and if its worth it $ wise.

    Questions;

    - Do you have a problem running low speed through your solar panels, and do you have a method to start the pump on high to get the system going then switch to low? I have a Suntouch controller that can start the pump on high speed initially then switch to low speed after 5 minutes.
    - Is a pumps rate and efficiency dictated by the housing, motor, or both. I could get an replacement motor (http://www.poolcenter.com/motor_parts.htm) thats' 2 speed and 3/4HP for under $300. But would that replacement motor be as good as a Superflo or Whisperflo (I like the Pentair brand, lol).
    - Can I take a 1HP Superpump and put in a 3/4HP 2 speed motor, or does it have to be a 1HP motor?
    - How much power do 2 speed pumps save? [edit: I think I found the answer (about 1/2 the flow and 1/4 the power)]

    My Specs;

    - 16x32 plaster pool, est. 24k gal.
    - Hayward Superpump, 1HP, a few years old
    - Pump pad is about 4' above pool waterline
    - 1-1/2" plumbing to/from pump
    - Pentair Suntouch Controller
    - 36sf DE Filter
    - 2- 4x12 Solar Panels, 2nd story


    Thanks!
    Kevin
    16x32 Concrete IG
    Equipment: Carvin 525sf Cartridge Filter, Jandy Gas Heater, Vortex Solar Panels w/solar valve, 1hp Hayward Pump with 3/4 HP AO Smith 2 Speed Replacement Motor, Aquarite Saltwater Cell, Polaris 280 Dolphin Active 20 Robot
    Automation: Hayward Prologic Controller

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    linen's Avatar
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    Re: Questions for Mark

    If it is a 1/2 hp whisperflo for example, it will move more water than say a 1 hp superpump. You really need to look at the curves, hp does not tell much.
    TFP Expert who uses Pool School and my TF100 test kit along with PoolMath for my: Round 11K gallon AGP with deep end, 20" sand filter, Matrix 1hp 2spd, 6 2ftX20ft solar panels (and solar cover!), Intex SWCG (copper bars disconnected) and a Rubadub hot tub (chlorine). The SLAM process is not finished until: 1. CC < 0.5 ppm, 2. An OCLT < 1.0 ppm and, 3. The water is crystal clear.

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    msgtdan's Avatar
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    Re: Questions for Mark

    Keep in mind that if you drop the motor h/p below the pump rating you'll need to change the impeller to match.
    Dan D
    Used 2003 Aqua Leader 27'x52", 17,800 w/10" hopper, SwimPro SW256T 250# sand filter, Hayward PowerFlo LX pump 1hp impellor, Emerson 1 1/2 hp motor, setup Aug 2012 Summer 2011 used Summer Escapes Ring pool 14' x 42", Intex 1600gph sand filter, HTH 6 way test kitTF-100 w/stirrer, Well water @ FC=0, PH=7.2, TA=290, CH=320

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    mas985's Avatar
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    Re: Questions for Mark

    Quote Originally Posted by kevreh
    Hi Mark;

    I saw your specs in your signature as;

    "18'x36' 20k gallon plaster/gunite pool, 1/2 HP 2sp pump, Aqualogic PS8 SWCG, 420 sq-ft Cartridge Filter, 450 sq-ft EPDM Solar Panel, 6 jet spa, 1 HP jet pump, 400k BTU NG Heater"


    That gave me pause as a 1/2 HP pump for a 20k pool AND filter AND Solar Panel (on the 2nd story, mentioned in a thread) seemed very underpowered. I currently have a system somewhat similar to yours (specs below) and am considering a 2 speed pump, downgraded to 3/4HP. I have a 1HP Superpump now and am wondering if I should replace it and if its worth it $ wise.
    First some background. My pump is a bit of a mishmash. It has the wet end of a 1/2 HP Northstar and the motor of a 1 HP Superpump. I call it my FrankenPump. The head curves for a 1/2 FRHP Northstar and a 1 URHP Superpump are about the same which is why I could use the Superpump motor on the Northstar. So the pump isn't really as small as it appears.


    - Do you have a problem running low speed through your solar panels, and do you have a method to start the pump on high to get the system going then switch to low? I have a Suntouch controller that can start the pump on high speed initially then switch to low speed after 5 minutes.
    I don't run solar on low speed because low speed does not generate enough pressure to keep a VRV closed when it is installed on a two story roof. I could have lowered the VRV to allow low speed but my controller only allows high speed during solar demand periods.


    - Is a pumps rate and efficiency dictated by the housing, motor, or both. I could get an replacement motor (http://www.poolcenter.com/motor_parts.htm) thats' 2 speed and 3/4HP for under $300. But would that replacement motor be as good as a Superflo or Whisperflo (I like the Pentair brand, lol).
    Primarily it is the impeller that determines the head curve of the pump and thus how much energy the motor will draw. The diffuser and volute also contribute but those are usually fixed for a particular pump line and only the impeller and motor is changed for different "sized" pumps.


    - Can I take a 1HP Superpump and put in a 3/4HP 2 speed motor, or does it have to be a 1HP motor?
    It is the impeller that determines the shaft load and the power required from the motor. So the motor must be sized for the impeller. However, the motor can be bigger than what is called for, just not smaller.


    - How much power do 2 speed pumps save? [edit: I think I found the answer (about 1/2 the flow and 1/4 the power)]
    Correct, if you compensate for the flow rate, a two speed will save a little over 50% of the energy costs.
    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: Questions for Mark

    Thanks mark.
    16x32 Concrete IG
    Equipment: Carvin 525sf Cartridge Filter, Jandy Gas Heater, Vortex Solar Panels w/solar valve, 1hp Hayward Pump with 3/4 HP AO Smith 2 Speed Replacement Motor, Aquarite Saltwater Cell, Polaris 280 Dolphin Active 20 Robot
    Automation: Hayward Prologic Controller

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