Cost of running 1.5hp vs 3.0hp well pump

[bhelts]

Hello.
I have been getting conflicting information from the person that drilled my well and the person installing my pump. So I came here to get a third opinion.

I'd like to know whether a 1.5hp, 5gpm well pump (400 ft well, pump level 280 ft) will use half the electricity to run as a 3.0hp, 10gpm well pump for the same amount of water?

There seem to be quite a few variables: total cost, cost/gallon, start stop count, lifetime of the pump. Any help would be greatly appreciated.

Any questions, I should be able to respond quickly.
Thanks!

 

[Valveman]

Both of those pumps are way over staged for a 280’ pumping level. You would have to run a minimum of 50 PSI against them (50/70 switch) to keep them from being destroyed on upthrust. Even with 50 PSI backpressure the 5 GPM pump is going to produce 8 GPM, and the 10 GPM pump is going to put out 16 GPM.

And if that is a “pump setting level” of 280’ instead of a “pumping level” of 280’, the problem is even worse.

Electric cost per gallon will be the same because the 3 HP just puts out twice as much water as the 1.5 HP. But the 3 HP cost twice as much to purchase and/or replace.

Do you need 16 GPM, or will 8 do the job? I think a 10 GPM, 1.5 HP would be a better fit for your well, as it will do about 12 GPM at 280’ and 50 PSI pressure.

 

[Sponsor]

 

[bhelts]

Both of those pumps are way over staged for a 280’ pumping level. You would have to run a minimum of 50 PSI against them (50/70 switch) to keep them from being destroyed on upthrust. Even with 50 PSI backpressure the 5 GPM pump is going to produce 8 GPM, and the 10 GPM pump is going to put out 16 GPM.

And if that is a “pump setting level†of 280’ instead of a “pumping level†of 280’, the problem is even worse.

Electric cost per gallon will be the same because the 3 HP just puts out twice as much water as the 1.5 HP. But the 3 HP cost twice as much to purchase and/or replace.

Do you need 16 GPM, or will 8 do the job? I think a 10 GPM, 1.5 HP would be a better fit for your well, as it will do about 12 GPM at 280’ and 50 PSI pressure.

valveman, thanks for the response.

I don't know about upthrust or backpressure. We have to push the water vertically about 400' and horizontally about 4000' to get to our last tank. Does that change things?

Obviously I don't know much about wells or pumps, I appreciate your help!
Thanks again.

 

[Valveman]

Horizontally won’t make much difference if you use large enough pipe, but the 400’ extra lift after the 280' in the well makes that pump fit much better.