Well woes

[Patches429]

Hey, newbee here... I have a 68ft deep well, 1 1/2hp submersible pump, (I know its overkill...but I own it)the surface level of the water is ~15' down & I want to place the pump at 60 ft. Will use 1 1/4" pipe to the house which is ~10' uphill from the well ~80' from the well, and continue uphill ~90' to a 3000gal. reservoir tank ~20' uphill from the pressure tank under the house. I do NOT know what the refill rate is on this well yet...During my search for a 1 1/4" pitless well adapter, I was told that the pump is to large and that it would not ??develop/maintain head pressure?? Can't recall all the clerk at the plumbing supply place told me, was hoping one of you guys/gals could give me a hand with my dilemma!! Mind you, I am not a plumber... Just a green electrician with some construction experience rebuilding an old homestead!!

 

[LittleInch]

Ok, a few questions.

Is this a 1.5 hp pump or 0.5?
Can you post the pump curve or give us the pump type, supplier etc.

In reality, so long as you have some sort of flow control I can't see the issue here. You'll waste some energy as your max flowrate is probably to much for your well but that's your call.

The only thing I can think of is that the pump if not controlled will pump too fast and could trip the beaker, but without the data requested above it's very difficult to say much more.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[bimr]

The well recharge rate is based on the underground aquifer and it is impossible to predict.

The issue will be pump cycles. Because of the high capacity pump, the well will be cycling on/off. If there are too many cycles over a short period, you may end up burning up the pump motor.

 

[Artisi]

Without knowing the available well yield and without having a pump curve and a calculated head loss, the answer to your questions ????????????.
When the well was drilled and developed, did the well driller establish the yield?
If the standing water level is 15ft why are you installing at 60ft - was this based on the well drillers advice?
Without the above info, the only real problem I see initially is you might overpump the well, however this is not the end of the world - either a flow control sensor to shut down the pump or impose some artificial head on the pump to reduce flowrate will cure your concerns.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[someguy79]

Is this a system you already have running, or are you in the process of building it?

I assume that you're installing the pump at 60' down (instead of at water level) so that you can pump down the well, then allow it to refill.
Iassume that the 1.5 hp is the motor's nameplate horsepower.
I also assume that your well pump discharges to a reservoir tank that's at atmospheric conditions. (i.e. It isn't pressurized.)

You can estimate the absolute minimum power needed if you know the flow rate, pipe size, pipe material, and elevation change. Even better would be to have the pump's performance curve also.

What's the total pipe length between the well pump and reservoir? (260 ft?)
What's the difference in elevation between the well pump and the highest point in the pipe or reservoir tank? (90 ft?)

Depending on how you're controlling the pump, on/off cycles might be just fine, and speed/flow control might not be warranted. Simple level control could be OK. In the reservoir could be a low level switch to start the pump, and a high level to shut off. In the well you would also need a switch to shut off the pump on low well level.

Of course, as the on/off cycle gets shorter, more sophisticated methods may be needed. These could include:
- other level switches to control dead band for start/stop,
- throttling valves,
- variable speed drives, and
- a myriad of other options.