Determining GPM from a well pump

Discussion in 'Irrigation' started by ArTurf, Jun 7, 2012.

  1. ArTurf

    ArTurf LawnSite Gold Member
    Male, from Ark
    Posts: 3,439

    What method do you like to use to determine your GPM from your water source? I do not have a flow meter. Does pump performance diminish over time due to worn impellers & etc? I do not work on many systems with supply from a well. There are hose bibs to work from.
     
  2. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Posts: 47,369

    You get in the ballpark by way of the educated guess, knowing the pump horsepower and the usual "drawdown depth" of wells in the area.
     
  3. ArTurf

    ArTurf LawnSite Gold Member
    Male, from Ark
    Posts: 3,439

    I realize now I did not explain the situation very well. I have a new customer whose system is on a well. At the end of last year the system began to lose pressure. When he fired it up this year the zones with a higher gpm would not even pop up due to lack of flow. Some of the smaller zones will work so-so but the lack of pressure is noticeable. At the beginning of this year he had someone install a new pressure tank.

    I am going to take a gpm reading from a hose bib off the system using the 5 gallon bucket test. Does anyone have any better ideas?

    I suppose pumps lose efficiency over time due to worn impellers & etc?
     
  4. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Posts: 47,369

    It might be more likely to suspect a lower water table than a pump wearing down. I do believe a pump can lose effectiveness from worn internal components. Certainly, I've seen well installs lose performance over a year or two, prior to the pump getting replaced.
     
  5. Mike Leary

    Mike Leary LawnSite Fanatic
    Posts: 21,909

    www.betterwaterind.com/flowmeter.html
     
  6. ArTurf

    ArTurf LawnSite Gold Member
    Male, from Ark
    Posts: 3,439

  7. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Posts: 47,369

    If an existing system is now 'sick' you don't need flow-measurement tools, you need a well-water pro on the site.

    Besides, there is a very easy way to use a homemade 'roofers square' and the water flowing from an open pipe to get a flow rate.
     
  8. 1idejim

    1idejim LawnSite Fanatic
    Posts: 9,328

    measure the flow close to the well head and before the tank. boots framing square method is accurate but is normally used in large diameter pipe low pressure situations, mainly in AG
    Posted via Mobile Device
     
  9. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Posts: 47,369

    Thing is, once the performance of an existing well starts to droop, there is little the sprinkler guy can do. You could re-nozzle heads to change the flow in a zone, but that is labor-intensive, and a waste of time and money, once the pump is replaced and the original performance restored.
     
  10. jcsmith

    jcsmith LawnSite Member
    Posts: 6

    Last week I had a similar issue not enough pressure on all zones. All electrical measurements were acceptable. Pulled the pump and the galvanized male adapter on the pump discharge was corroded, almost broke off. Also earlier in the season had another system that some of the heads on all zones would not popup but the ones that did not popup could be pulled up and stayed up. It was almost a vacuum holding some of the heads down. Pulled the pump and the galvanized male adapter on the pump discharge had a hole in it.
    Posted via Mobile Device
     

Share This Page