Grundfos well pump

Oscar13601Oscar13601 Registered Users Posts: 18
I have a well 165 feet deep in upstate NY. I'm looking for a pump that would work with no hassle. I was looking at the Grundfos 25 SQF-7, Centrifugal, 185 Feet, 39 GPM, 130-1400W pump. I just find out the meaning of MAX HEAD pressure, which is zero water flow. Now, this pump having a 185' Max Head Press would it work??? I'm planning on having a min 120 gal pressure tank. Being now 185-165= 20 feet, how much flow (GPM) em I really going to have to fill the tank (if I go with this pump). What is your thoughts??? What other pump you guys think would work??? I'm looking to have at least 20 GPM to fill the tank. I'm very new at this... : )



  • BB.BB. Super Moderators, Administrators Posts: 31,614 admin
    Re: Grundfos well pump

    You also need to take into account the pressure for your home too... Say you want 40 PSI, then that would be another:

    40 PSI / 0.43 PSI/FT for fresh water = 93 feet of head for 40 PSI pressure tank

    If your lowest water level in the well is 165 feet water level + 93 feet for head + XX feet for pipe losses = 258 foot head minimum

    From the Grundfos manual (PDF download), the 25 SQF-7 is rated for (page 30) 185 foot head at 1,400 watts and 15 GPM... It is not rated for your head. If you where pumping to a cistern and had a separate pressure pump/system from the cistern, then it would work (assuming level ground--you have to add water level height to the cistern and/or if home is uphill from well).

    A 6 SQF-2 would supply about 5.5 GPM with a 560 watt array at 295 foot head.

    Or a 11 SQF-2 would supply 295' at 10 gpm and 950 watt solar array.

    At least that is how I read the charts (just a quick glance--read the whole manual. Lots of good information).

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • tmarchtmarch Solar Expert Posts: 143 ✭✭
    Re: Grundfos well pump

    If the well is 165 feet deep odds are the static water level is above that. The static water level when pumping will determine your head, as the pump only has to lift water from that level, then add in the other figures. I always try to go a size bigger on the pump if I don't know the draw down when pumping unless I know the recovery rate of the well.
    20 GPM is A LOT of water for household use.
  • Ralph DayRalph Day Solar Expert Posts: 940 ✭✭✭✭
    Re: Grundfos well pump

    I can't imagine 20gpm for household consumption. That's almost enough to fight a fire with:confused:. Perhaps it was 2.0?

    I have a booster pump on my outside tank, pressurized in the house, delivering 2.5gpm. It's fine for any fixtures, they are all low flow faucets and showerheads to about 2gpm. Don't want a flush to happen when someone is in the shower, but otherwise all the needs are met at 2.5gpm. When the house goes on the Grundfos submersible pump for whole house service (usually only well water for drinking), you really notice the difference in pressure and flow rate (10gpm vs 2.5gpm).

  • stephendvstephendv Solar Expert Posts: 1,571 ✭✭
    Re: Grundfos well pump

    Don't know if the mods are going to delete the last post because it's clearly SPAM, but it is an interesting product! It looks like the company offers a VFD drive for generic 220V 3 phase pumps with built in MPPT that you can connect panels to directly.

    Guess what? :D - Cariboocoot
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