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Pumper

New Member

Posts: 3

Location: USA

1

Wednesday, June 1st 2005, 12:21pm

Gallons/Minute?

I have a question and I may be over-thinking it. I am about to go home and measure my pressure and GPM. I am on a well (3"main with a 3hp pump). I will probably stub out from the well site which is a 1.25" pipe. I was planning on measuring my GPM from the hose bib at the well site, but, to me seems like it would be more restrictive than the 1.25 pipe. The water sprays about 8' out from the bib, will I get an accurate GPM? I know I have a high pressure based on the fact that if I leave a hose connected to the house with the faucet on and a nozzle on the end (off) it will eventually balloon out my hose. Is there a better way to measure the GPM or will I be ok? Also, the only way I know to measure GPM is to fill a five gallon bucket and doing the math after I see how long it takes to fill it. ANY and ALL advice is appreciated. I have installed my own systems on city water, but, not on a well. I have used T-Birds in the past but since they are no longer made was thinking of the Hunter PGM's. Thanks to all.
Bill V

RidgeRun05

Supreme Member

Posts: 314

Location: USA

2

Wednesday, June 1st 2005, 6:45pm

The best way to get an accurate measurement is closest to your POC (Point of Connection) for your sprinkler system. If this hose bib is closest to your POC, then use it to do your calculations. Without buying an guaging tools, your best bet for GPM is to fill the five gallon bucket and do that math. You can measure your PSI with an inexpensive pressure gauge that will screw right onto the hose bib. (You can get a cheap guage at any home improvement store).
Tony Posey
Ridge Run Landscapes

Pumper

New Member

Posts: 3

Location: USA

3

Friday, June 3rd 2005, 4:07am

Thanks,
Now...I did my pressure and GPM measurements. I was pumping 15 GPM, but, my pump kept cycling off and on maintaining my PSI between 42-47PSI (pump kicks on at 42 and off around 47-50, the press. gauge at the well is reading 60psi). From what I have been reading, you dont want your pump to cycle off and on, is this correct? What should I do next? My thinking is that if I put someone at another hose bib (or two if need be)with a hose(s) running at the same time I am measuring my GPM on the bib at the well origin, and the pressure stays above 42 I could then add the two together. Will that give me a more accurate max. GPM and prevent my pump from cycling on and off? I dont want to ruin my well pump (3hp). Thanks
Bill V

Wet_Boots

Supreme Member

Posts: 4,028

Location: Metro NYC

4

Friday, June 3rd 2005, 6:44am

Get the water level information on your well. The drawdown level (distance below surface the water level is when pumping) is what you'd use to check against the performance tables of your particular pump. Trade the five gallon bucket in for a garbage can. Odds are, you will be running 25 to 30 GPM, and will have to size the sprinkler system to match.

Pumper

New Member

Posts: 3

Location: USA

5

Friday, June 3rd 2005, 10:36am

I guess I wasn't clear on my question/dilema. I think my hose bib is restrictive to the max flow. (Meaning, I think the max GPM through my hose bib is 15GPM and I will be able to flow more with adequate pressure through the 1.25" pipe) When I open the hose bib closest to the POC, it sprays out about 6 or 7 feet out from the faucet. I checked with two five gallon buckets and they filled in 40 seconds (15 GPM) But, as I said earlier, the pump is cycling on and off. I am unable to run enough water through the one hose bib to make the pump run continuously (that is my goal, correct?). If that is indeed my goal, will it work to open two hose bibs, check the pressure, and if the pressure is high enough with both open, measure and add the two hose bibs.
Bill V

Wet_Boots

Supreme Member

Posts: 4,028

Location: Metro NYC

6

Friday, June 3rd 2005, 12:36pm

Forget the hose bib. Mankind has not yet created a hose bib that will allow you to evaluate the performance of a three horsepower pump.

You should know the depth of the well, the depth of the pump, and the all-important draw-down level. See if the well/pump performance is on record at the well drillers or pump service company. If it isn't, and you want an accurate number, you will have to duplicate the 'bucket test' on a much larger scale.

Based on the 15 gpm figure you mention, you would plumb 1 1/2 inch pipe to the outside, and affix a shutoff valve to the outdoor end of the line. Then you can do a test with a pump hose into a 30 gallon trash can. Since you have to get the water outside anyway, you aren't wasting any effort.

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