How much increased well pump usage with Geo?

Discussion in 'Open Loop' started by eisensms, Jan 15, 2009.

  1. eisensms

    eisensms Member

    My current situation is:
    My Well pump power is 3/4 HP or approximately 800 watts.
    Average time well pump is really running in my house each month is 20 hours.
    kWh annual consumption is around 192 @ 10 cents per or approximately $20/year.

    So now I add a new Geo unit. How much will my well pump need to run
    per year more than what it is currently running? Just a rough guess will
    do. Thanks!
  2. thaas53

    thaas53 New Member

    I don't think you'd want to use your domestic water well to run an open loop, but others may know more than I.
  3. arkieoscar

    arkieoscar Member

    Many people do it. The amount of water is directly proportional to how big a system you need. The first thing anyone will ask is- How many tons of heating/cooling will you install. The new, variable speed pumps can help with pumping cost.
  4. eisensms

    eisensms Member

    installing a 4 ton unit

    Waterfurnace 4 ton water-to-water unit to be installed.
    Was just interested in how much my electric bill is going to skyrocket
    trying to make heat out of incoming cold water. ;)
  5. hardchines

    hardchines Member Forum Leader

    It will run allot

    I just installed a 3/4 hp well pump and I am running a 2 ton and a 3 ton @1.5 gpm, when both units run pump runs continuously, wish I installed a 1 hp pump.
  6. cattracker16

    cattracker16 New Member

    lots of variables

    I am a well driller/pump installer and have been for several years. a 3/4 pump would be fine, concidering the amount of water/ tank sizing is proper.

    On a "normal" system we supply a 10 GPM pump and a tank equal to 120 gal. so the actual tank may be 33 gallon, or you get aprox 5 gal of water out of tank before the pump runs through a cycle.

    If the customer tells us they are going with geo heating system, The system we usually install is at the min 19 gpm with a 200 gal equal tank.

    There is alot of variables, if you have a 3 wire pumping system you would be able to install a variable speed pump. if you have a 2 wire system it is possible to get the variable speed pump, but the wiring would have to be changed out to your well.

    I'll give you a little bit info from my system. I have a variable speed pump, it's capable of pumping 27 "GPM@60Psi". well depth is 200' with a capacity of 50 GPM @ 50' pump set 60 tank size is 20 gallon. i don't know if any of this will help. but i thought i'd put my 2 cents in.
  7. Palace GeoThermal

    Palace GeoThermal Well-Known Member Industry Professional Forum Leader

    the 4 ton heat pump will need at least 6 gpm.

    If it runs for 3000 hours a year, that will be

    6 * 60* 3000 = 1,080,000 gallons in a year
  8. hardchines

    hardchines Member Forum Leader

    FROM WHAT i HAVE READ AND BEEN TOLD BY some smart folks here is yes it will cost more for a 3/4 hp pump in the well compared to a circulater pump , but it should run less then a circulater closed loop system. I figure my 3/4 hp well pump is using about 2 amps. more then a loop system pump (s). As Cattracker said 3/4 is fine but I wish I had a bigger pump, I am getting 10 gpm with my new 3/4 hp pump, and I went way out of my way to optimize the pump flow for my well depth (pump is at 70 feet), I have three bladder tanks,1-40 and two 35 gallon tanks, about 34 gallon between pumps.
  9. waterpirate

    waterpirate Well-Known Member Industry Professional Forum Leader

    electric motor 101

    Just like a compressor, it is the starting and stopping that causes wear. The variable speed pump option truly is the only option you should consider for a variable demand. Make sense? You also gain variable consumption of electric.

    You can cheat the system by providing more storage, but you are band-aiding a condition that could have been avoided. If it was me I would rather have a pump on and running continuously than starting and stopping it to satisfy a geo load.

    A word on pumps. when you talk about water pumps we need to focus on the gpm deliveres first, then the hosepower needed to meet a specific target in feet of head/psi.

    I allways get a good laugh at the local Lowes. They have on the shelf: 1/2, 3/4, 1, and 1 1/2 hp pumps that are all rated at 10gpm. None of these pumps will pump much over 10 gpm but the difference in psi is huge.
    1/2hp maybe 65psi, the 1 1/2 you could use as pressure washer.
  10. ldameron

    ldameron New Member

    Hello Cattracker1:

    Have you ever used a cycle stop valve to stop the pump from cycling off and on?
  11. cattracker16

    cattracker16 New Member

    Yes sir i have, the only problem i see with the cycle stop is it creates bunches of pressure on the pump side of the valve.
  12. ldameron

    ldameron New Member

    Does this added pressure cause any problems? Does it cause harm to the pump? It sure makes my system better!
  13. waterpirate

    waterpirate Well-Known Member Industry Professional Forum Leader


    Hi and Welcome,

    Please see reply to your other post "cycle stop valve" for the nitty gritty.
  14. ncgeo

    ncgeo Member

    Just 800W running a 3/4 HP pump? ... must be 115V not 230V. My 3/4 HP pump is pulling 6 amps but that is at 230V, about 1.4kW. And my pumping level is just 20' below surface.
  15. moondawg

    moondawg Member

    I'll admit to knowing very little about pumps, but that doesn't sound very efficient!

    One horsepower is (roughly) 750 watts. You're putting in 1.4kW and getting out 560 watts of work.

    Of course i'm assuming that the 3/4 hp rating is a "max" rated output.

    someone feel free to educate me if I'm making a bad assumption somewhere.
  16. arkieoscar

    arkieoscar Member

    It's the law.

    How are we going to figure out the complicated stuff when people think Ohm's law is just a suggestion? Voltage won't affect the watts, just the current.
  17. moondawg

    moondawg Member


    Ohm's law: V = I*R

    Power: P = V*I <- Voltage most certainly affects the power consumed in a circuit.

    You can plug Ohm's Law into the Power equation to get a solution that doesn't rely on volts. P = I^2 * R (Power equals Current Squared times Resistance) ... but you can also figure it without the current: P = V^2 / R. (Power equals Voltage Squared divided by Resistance.)
  18. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    Ohm's law

    as a suggestion?

  19. ncgeo

    ncgeo Member

    Voltage does affect the power, as you're pushing the current through a greater potential difference. If you halve the voltage you double the current for a given power.

    But I do agree that 1 HP is about 750W which is far different than 3/4 HP using 1.4kW So not sure how or if I am figuring wrong here; I measured the 6 amps with 2 different clamp-ons. Isn't Power = Volts x Amps? Maybe has something to do with peak vs. RMS voltage (the 230 is peak-peak I think)

    It's been too long since my EE days in college however. Someone educate me on this. Maybe I'm vastly overestimating the power consumption of the pump.
  20. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader


    a power calculator.

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