Pump system design

GuitarmanGuitarman Registered Users Posts: 4
I am trying to figure out my plumbing system right now and am torn between using a slower dc pump or a grundfos. I found a used 5 gpm grundfos for sale online for 300 bucks, which is a 220 3 phase 2 wire pump. Does this need to be run with a VFD and a transformer, or just a transformer? I am still pulling my hair out over whether to do a gravity tank or pressurize and run into a large pressure tank. I am also trying to figure out how much more power production I would need to go with a higher powered pump. I currently have about 400 watts into 4 t-105s with a trace c-40 charge controller. Can't put too many more panels on the charge controller...
I have a Xantrex 1500 watt inverter, which obviously is looking kind of small. Much better than the truckstop inverter I've used for the last few years, though, right?
I have a honda 2000 generator.

The appeal of adding production is that the power could be used for other things besides pumping water, such as refrigeration. I am attracted to gravity feed because of the ability to control/minimize when the well pump operates, but discouraged because of the infrastructure work required. Tanks aren't free, either, and trenches don't dig themselves.
I've enjoyed all the good advice on other threads. Thanks for all the knowledge and effort put in on this site.

Comments

  • BB.BB. Super Moderators, Administrators Posts: 31,063 admin
    Re: Pump system design
    Guitarman wrote: »
    I am trying to figure out my plumbing system right now and am torn between using a slower dc pump or a grundfos. I found a used 5 gpm grundfos for sale online for 300 bucks, which is a 220 3 phase 2 wire pump. Does this need to be run with a VFD and a transformer, or just a transformer?

    I am still a little confused--Do you have a link to the pump/motor you want to get? A three phase motor is generally three wire, not two wire (two windings? A run and a start winding with external capacitor possibly?).

    A transformer cannot provide three phase power (it can supply split phase or two phases a 180 degrees apart--such as a center tapped transformer).

    You would need a VFD or three phase power source to run a three phase pump (or a capacitor start unit to provide a another phase). The capacitor or VFD provides the second or second and third phases to create the "rotating" magnetic field required to "turn" a motor.
    I am still pulling my hair out over whether to do a gravity tank or pressurize and run into a large pressure tank. I am also trying to figure out how much more power production I would need to go with a higher powered pump. I currently have about 400 watts into 4 t-105s with a trace c-40 charge controller. Can't put too many more panels on the charge controller...

    In theory, the two methods should use about the same amount of power. But a "slow pump" plus smaller pressurization pump may use less "peak current"--usually nicer for a battery based/inverter based system.

    I guess I would look at the structure/location of your tank and other issues (i.e., cleaning, freezing weather if any, any structure and "excessive plumbing" needed to support a gravity tank, amount of "above ground water storage" and any fire suppression storage needed--both for your use and possibly wildfire needs for fire department, etc.) to decide the type/size/location/pumping methods first.

    Then once you think you have a tank system that meets your needs, look at the pumps/power system needed to support such a system.
    I have a Xantrex 1500 watt inverter, which obviously is looking kind of small. Much better than the truckstop inverter I've used for the last few years, though, right?
    I have a honda 2000 generator.

    In the end, whatever works and supports you needs. TSW is always a nice end point--But for some it takes longer to get there (money does not grow on trees).
    The appeal of adding production is that the power could be used for other things besides pumping water, such as refrigeration. I am attracted to gravity feed because of the ability to control/minimize when the well pump operates, but discouraged because of the infrastructure work required. Tanks aren't free, either, and trenches don't dig themselves.

    I am no pump/tank expert... But I would probably suggest leaning towards a larger ground level tank and 12 or 24 VDC pump for pressurization (and even a pressure tank too to reduce pump cycling). Supports larger above ground water storage tank without the structure/trenching needed for gravity feed. In California and earthquake country--Ensuring water works don't collapse from ground motion is no little amount of engineering work for elevated water tanks.

    Of course, there is the cost and maintenance of a second pressurization pump to take into account (should last a few years between pump head rebuilding--Try to have the pump below water level to avoid having to pull a vacuum on the pressurization pump's input--lessens the whole air leak/poor performance/cavitation/inlet filter restriction issue).

    Others here can probably give you much more experience with cisterns and their advice.

    Good luck,
    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • GuitarmanGuitarman Registered Users Posts: 4
    Re: Pump system design

    Here's the link for the used pump I was looking at. I asked them for a model number, etc, but haven't gotten a response. http://www.wvpump.com/images/Complete_Pump_Systems.pdf
    Thanks for your prompt reply, Bill.

    P.S. I am in Wisconsin so any tank would be have to be buried. Question--what is "TSW"? Thanks
  • BB.BB. Super Moderators, Administrators Posts: 31,063 admin
    Re: Pump system design

    TSW--True (or pure) Sine Wave Inverter. And MSW--Modified square (or sine) Wave Inverter.

    A little information about them:

    All About Inverters
    Choosing an inverter for water pumping

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • icarusicarus Solar Expert Posts: 5,400 ✭✭✭✭
    Re: Pump system design

    How deep are you pumping from,, what is the total head, how many GPM/GPD are required?

    Tony
  • waynefromnscanadawaynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    Re: Pump system design

    Puzzles me why folks would be selling their used water pumps. Wonder if they're getting warn out and can't get the pressure up any more. I've seen it happen. Especially if the pump has been run dry, the well went too low and the pump sucked air, doesn't take long to ruin it. If it was working fine - - then why replace it? Buyer beware I suspect.
  • GuitarmanGuitarman Registered Users Posts: 4
    Re: Pump system design

    According to the WV pumps website, the used wells they sell are ones that their customers upgrade from, in some cases they are reconditioned by the company's in house shop. Still, though, I can see your point. Only thing might be if they need more capacity.
    In general I always shy away from buying new whenever possible, but this may be a situation when I should curb this habit.

    In response to the question about flow and demand, I am not entirely sure. I believe the well is 100 feet deep and I think the water sits at about 30 feet, possibly less. Right now I have a cast iron hand pump. We've been in drought here this summer and I've started to see debris coming in the well, looks like mostly galvanized pipe flecks. Is this a sign of the well getting down too low? I hope not.

    I suppose I ought to get a well guy out to assess the levels and flow rate of the well before I figure out how much draw down I can actually handle.

    As far as usuage, right now we use about 30-40 gallons a day, but that is mostly because we have a hand pump. And we have a baby coming in one month so I am trying to get things in shape to wash diapers and not have to haul buckets.

    Thanks for replies thus far--what a helpful forum!
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