Become a TFP Supporter Pool Math Forum Rules Pool School
Results 1 to 8 of 8

Thread: Questions about my newly installed 2 speed pump

  1. Back To Top    #1

    Questions about my newly installed 2 speed pump

    So earlier this week, my pump went out. I wanted to get a two speed pump to try and see some energy savings and the benefits of a quieter pump is nice too. I ended up ordering a Hayward Max Flo II 1 HP, Model SP2707X102, which is actually a 1.25 HP accounting for the service factor. On high speed, this has a little more power than the previous unit which was 1.1. On low speed it will consume much less energy than the previous unit, or at least that's my hope. It wasn't the most energy efficient unit available, but should get me in the ball park of where I want to be I think. I ended up buying this unit based on the dual speed feature, price, and availability. I picked it up for $418 with FedEx Overnight Shipping and installed it today. So on to the questions. On low speed, I'm running about 5 psi on my gauge. On high speed I'm around 10-12 psi. Is this what I should expect? I know that resistance drops as well with reduced flow rate, so I'm just trying to make sure that everything is working as it should. How can I be sure that I am getting the proper amount of flow that I need? I don't have a switch installed right now so I can only be wired in at one speed or the other. I'm thinking of playing with my timers a little if I can figure out what my actual estimate GPH filtration is and can set my pump to run however I need to. Right now I would be content to run the pump 24 hours a day on low speed if that gives me enough filtration and use the swtich to go to high when cleaning, backwashing, etc. Also, I know that some old school people have said that running my pump in low speed will burn it up do to too much strain against the motor. Is there anything I need to be on the lookout for? How do I know that the pump is actually up to the task?
    24,000 G, Sand, IG, Vinyl

  2. Back To Top    #2
    Mod Squad Bama Rambler's Avatar
    Join Date
    Jun 2009
    SouthWest Alabama

    Re: Questions about my newly installed 2 speed pump

    As long as it's moving water you can run it on low forever. Since you have a sand filter you will need high for backwashing that and probably vacuuming. Though some people vacuum on low as well.

    Your pressures seem about right. I suggest that you use the pressure on high speed to determine your base pressure to go by on when to backwash the filter.
    Dave J. TFP Moderator
    24' x 52" Round AGP. 2hp/¼hp SPL Power-Flo 2-speed pump. 200sqft Waterway Cartridge Filter. 45MHP2(3GPD) Stenner Peristaltic Pump
    Pool School ----- Pool Math ----- TF-Test Kit

  3. Back To Top    #3

    Re: Questions about my newly installed 2 speed pump

    I have to correct myself. PSI is around 2.5-3 not 5.

    IIRC, which I might not, when I was interpreting some of the info in this section when you drop the speed of the motor, your Flow drops by 1/2, the energy consumption drops by 1/8 and the resistance to flow drops about 1/4. Is that correct? If so then that would make sense if my high speed PSI is 10 and the low speed PSI is 2.5.
    24,000 G, Sand, IG, Vinyl

  4. Back To Top    #4
    linen's Avatar
    Join Date
    Jul 2010
    Twin Cities, MN

    Re: Questions about my newly installed 2 speed pump

    My 2 speed matrix with a clean filter runs at 16-17 psi on high and 5-6 on low.
    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.

  5. Back To Top    #5

    Join Date
    May 2011
    Bensalem PA (Philly Suburbs)

    Re: Questions about my newly installed 2 speed pump

    I have a pentair cc 200 filter, and it's running at like 1 psi on low, 10 on high. At first I thought my gauge was broke because it has so little psi on low...
    18' x 38' x 52" oval AGP with 6' deep end (foam on the walls, preformed coving, and Happy Bottom floor padding)
    Pentair Optiflow 1 HP 2 Speed pump
    Pentair cc200 cartridge filter
    Pentair UltraTemp Model 110 BLK 108,000 BTU Heat Pump
    2 Intex SWG's (copper unplugged)

  6. Back To Top    #6

    Re: Questions about my newly installed 2 speed pump

    So based on this rule of thumb, Return Dynamic Head = 2.31 * Filter PSI + 3, I would be around 26 on high and 8 on low. Hayward list the low speed flow for my pump at 27 GPM at 10' of head, so I should be flowing slightly higher than that. But even if I use the 27 in order to be a hair conservative, I will filter almost 39,000 gallons in a 24 hours period. Am I on the right track?

    Also based on some rough numbers. I'm thinking that my energy usage with my old pump was costing me around $30 a month, based on my new numbers it looks like I will be down to a little over $8. I'm not sure if my math is right but if so, I'm pretty excited about that.

    Old pump 1.1 HP - 825w per hour @ 12hrs per day * 30 days @ ~.10 per kwH = $29.70 a month
    New pump 1.25 HP 117w per hour(937 kwH on high/8) @ 24hrs per day *30 days @ ~.10 kwH = $8.44
    24,000 G, Sand, IG, Vinyl

  7. Back To Top    #7
    JasonLion's Avatar
    Join Date
    May 2007
    Silver Spring, MD

    Re: Questions about my newly installed 2 speed pump

    Actual energy use doesn't actually go down that much. Typically a two speed pump uses right around 1/4 as many watts on low as it does on high, for a 50% savings over high after you take into account running it for twice as long to get the same total amount of water moved.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

  8. Back To Top    #8

    Re: Questions about my newly installed 2 speed pump

    The pump actual says 1hp on high and .16 on low. Not quite an 1/8 drop but still over 1/6
    24,000 G, Sand, IG, Vinyl

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts