What pump choices for a 400 ft well,residential use only

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Timbuktu

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I have a 400 ft well.

static level is 140 ft

Pump is 1.5 hp ( It delivers 16 gpm until watersource is drawn down to a pumpTec low water stoppage.)

Casing OD(what you see on the concrete deck) is about 6-7"dia. I dont know the innards dia.

QUESTION:
1-Would using a smaller well motor be more energy efficient?
2- Would a smaller motor tent to have a longer lifer?
Im not having any water supply problem. im just trying to keep motor price and operating cost down without decreasing my water demands.
.


i live in the high desert in southern california. i live in a mountain/canyon at 3400 ft.
Most well water sources up here are of the fissure type and low output wells as a result .
I have a 2200 water storage tank for that reason primarily.

My current well motor pumps the water from the source (400ft below) and into the sto tank and cycles off after about 10 to 15 min of pumping.
What would be a better choice to replace the current 1.5 hp motor with when it eventually fails?
Oh...Here are some other details.
.
1-The well water source below supplies with a variable .42 gal per minute to as much as .6 gpm.
2-My water use is 300 gal in the am and 300 gal in the afternoon for all plants. That about the max I would use in the hottest of summers,june to oct. That leaves me 100 + gal per day for so gal distributed during waking hours
The water tank is alway full by the next days watering schedule time.
The last 6 years this water need/supply/usage has worked fine.

These numbers below arent exact as they all vary considerably day to day. Im just trying to give you a general idea of the the well ouput and my use, so as to help decide on what pump may be a better for my situation than my current 1.5 hp motor.


Thx
 

DonL

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A flow restriction on the output of the pump may work, So that you do not suck more than the well can produce.

You need some power to get the job done, and a smaller pump may not be the best answer.

I work on Rockets , but the theory works.


Good Luck.
 

Valveman

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It doesn’t matter is you are running a 16 GPM, 1.5 HP pump for 15 minutes, or if you are running a 7 GPM, ¾ HP pump for 30 minutes, you are using the same amount of energy. It takes X amount of energy to lift Y amount of water from Z feet of head. Using the most efficient pump you can find for the particular application is the best you can do as far as energy consumption goes. And there is not much difference in efficiency of these type pumps.

The pump you have will supply 16 GPM until the water level in the well drops below 300’. Then from 300’ to 400’ the production of that pump drops off to about 2 GPM. So if you shut the pump off when the water level pulls down to 300’ instead of 400’, you will be getting more gallons per kilowatt. The pump would only be able to run about 10 minutes at a time instead of 15 minutes. This means it would have to come on about 30% more often, and run 30% less per time, to supply the same amount of water. This way you are only lifting from a max of 300’ instead of 400’, which would save some energy.

Although, I bet you won’t save enough energy doing this to be able to measure much difference. Bottom line, you won’t be able to decrease the operating cost without decreasing water demands. Whether the pump runs 10 minutes or 15 minutes at a time is not going to make any difference in the longevity of the pump system either.

Sorry DonL. I was typing and didn't mean to step on you. But the less restriction you have, the more gallons you get per KW.
 
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DonL

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Sorry DonL. I was typing and didn't mean to step on you. But the less restriction you have, the more gallons you get per KW.

No problem.

I was thinking about pump cycles and not power saving.

No Free power in this case.
 

Timbuktu

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pump choices

I have had two pump/well drillers say the pump is too large for my well. These comments were over a few years time and were brought up by me during casual conversation regarding other issues not related to the pump motor.
yes it could have been a subtle sales job,but wasnt an abvious one. In the end,if one knows virtually nothing about these matters ,which applies to most residential well owner,then its easy to sell a job to the customer.

So, when the day comes that i need to swap out my pump motor due to failure,are there any other pump recommendations besides or "just replace it with tthe same unit"?
 

DonL

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I have had two pump/well drillers say the pump is too large for my well. These comments were over a few years time and were brought up by me during casual conversation regarding other issues not related to the pump motor.
yes it could have been a subtle sales job,but wasnt an abvious one. In the end,if one knows virtually nothing about these matters ,which applies to most residential well owner,then its easy to sell a job to the customer.

So, when the day comes that i need to swap out my pump motor due to failure,are there any other pump recommendations besides or "just replace it with tthe same unit"?


Just get the calculator out and see what you need.

There are a few Variables in the formula.

There are online calculators that can do a best guess, for the HP and size of wire required. Your wire should be fine if you go with smaller pump at the same Voltage.


Have Fun



Good Luck.
 

Timbuktu

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A flow restriction on the output of the pump may work, So that you do not suck more than the well can produce.

You need some power to get the job done, and a smaller pump may not be the best answer.

I work on Rockets , but the theory works.


Good Luck.
so far its still working 09-30-17 4 yrs
 

Timbuktu

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Woops I forgot to say I had it replaced with the smaller pump shortly after and its been in 4 yrs. The well man though it would be best for my 400 ft well 250 static line and production of .4 to .6 gpm....all pumped into a 2200 gal tank. How much longer....we'll see
I wasnt going to argue with him . Thx for your imput anyway rocket man...no that title now belongs to kim jung un ...sorry
 

Valveman

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A 1.5HP, 16 GPM pump can barely lift anything from 400'. It was probably not able to pump any water from 400', so the pumptec was not sensing a dry well condition and was most likely not shutting the pump off when it should. This would make the motor/pump get hot and shorten its life.

A 10 GPM, 1HP pump will still be pumping 3 GPM from 400', so it will pump the well dry and the pumptec should be able to shut off the pump as it should. If you replace the pumptec with a Cycle Sensor, it would be sensitive enough to shut the pump down even before the well pumps completely dry. With the Cycle Sensor you can actually see the amps. So you can set it to shut down at the amps that happens when the water level gets deep, and before it starts pumping air.

Sometimes a pumptec just can't tell the difference between low flow and no flow like a Cycle Sensor can.
 
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