Grundfos for deep well decision

System
System Posts: 2,511 admin
I am trying to decide on the 3 SQF-3 or the 6 SQF-3. I have 625 ft of head pressure. According to the flow charts the 3 SQF will pump more but it is at the top of the chart compared to the 6 SQF. Will the pump not last as long? I have 4 185 watt panels I can devote for water pumping. Does anyone have either of these pumps in service and how are they working for you? I originally wanted to do a jack pump because I thought that was my only option for this deep of well but now I'm leaning towards these submersible pumps. Any opinions?

Comments

  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Grundfos for deep well decision

    Welcome to the forum.

    If you look at the pump chart you see the 3 SQF-3 can handle up to 600 feet of lift but only pumps 2 GPM at that depth. The 6 SQF-3 will pump 6 GPM @ 820 feet. This is always a trade-off for any given size pump: greater lift means less flow and/or pressure available. Go to a bigger pump and you need more power. The 3 series is listed as needed 900 Watts of PV to achieve its maximums, whereas the larger 6 requires 1400 Watts.

    As a general rule, you are correct in surmising that a pump operating closer to its maximum limits will not last as long. This is true of just about anything, in fact. It is also why plumbers frequently install over-sized pumps - and then their customers come on here looking for ways to power the things with PV. Often pool pumps fall into this category. :roll:

    For exact information on how well either would work, get your details together (740 Watts of panel, well depth, static head, distance and pressure requirements) and contact either NAWS or Grundfos. You really don't want to be guessing at this.
  • System2
    System2 Posts: 6,290 admin
    Re: Grundfos for deep well decision

    I did call and talk to NAWS with all my relative info on my situation I was told I could use either pump and it was up to me. The 6 SQF-3 could have more panels added to it if I wanted more power where the 3 SQF-3 was maxed on power. I was told that the smaller pump should pump more at the lower power though. Im leaning towards the 6 SQF-3. Does anyone have any experience with the Lorentz brand solar pumps? their numbers look impressive but I'm not sure how good of quality they are. Any other suggestions or options out there besides Grundfos. I am getting close to buying a Grundfos pump and I want to make sure there isn't a better option out there before I purchase.
  • Volvo Farmer
    Volvo Farmer Solar Expert Posts: 209 ✭✭✭✭✭
    Re: Grundfos for deep well decision

    I have a Lorentz, and it has been working great for 2 years now. The guy I bought it from preferred it to Grundfos because the electronics were not down the hole and should an electronic failure occur, the pump would not have to be removed. I did have a problem with the circuit board in the first year, it lost its protective coating, I think because of UV exposure, and I didn't have the lid on the control box. Well, the frost in the morning would freak out the board until it dried out in the afternoon. I emailed for warranty and actually contacted Mr. Lorentz himself in Germany. I had a new controller within a week.

    The really neat thing about Lorentz IMO, is the rheostat on the board. We have a really low producing well here, somewhere around 1GPM. A hydrologist told me the worst thing for a well like this is to draw the water down 100' in the casing every time the pump comes on. She said if I can maintain the static pressure in the well, I would have much fewer problems with turbidity. We pump into a cistern and use less than 500 gallons/week. I can pump slowly enough with this Lorentz to keep my turbidity to a minimum, yet we still have all the water we need of this low producing well.

    We only have about 100' of head but are powering it with a single 170W panel.
  • tmarch
    tmarch Solar Expert Posts: 143 ✭✭
    Re: Grundfos for deep well decision

    I have both Grundfos and Lorentz pumps installed and working.
    Grundfos looks simpler, but I like the Lorentz better.
    Lorentz pumps are modular, motor and pump are seperate and they are the only things in the well itself. Grundfos is all in one unit.
    The other thing I like about Lorentz is that I'm using the helical model and it will handle sand or any other solid better.
    Lorentz also has a adjustment in the control box to vary the amount of flow.
    My pumps are producing 5 GPM @ 280 feet, the Grundfos with 640 watts of panels and the Lorentz with 700 watts.
  • System2
    System2 Posts: 6,290 admin
    Re: Grundfos for deep well decision

    I just ordered my pump Grundfos 6 SQF-3. Thank you for the information. I will post the performance after installation if anyone is curious.
  • DaveR
    DaveR Registered Users Posts: 5
    Re: Grundfos for deep well decision

    How is your Grundfos 6 SQF-3 working out? I have a similar well (660' lift) and similar solar amount of solar power (four Suntech 210-watt panels), and have had bad experiences with Lorentz PS1200 pumps. Two pumps failed (both pump motors stopped turning, even when my meter showed >8 amps at >100 volts going down the wire to the pump), and 1 controller went bad (started smoking when returned for repairs). Grundfos 6 SQF-3 is the one other direct solar pump I have seen that is rated for this lift.
    Does anyone else have recent experience with these pumps (or others for that lift)?