Gene wrote:
Problem: Design a pumping system for this rural water well:
- we have a new 240' water well with 6" PVC casing on
some rural ranch land north of Austin, TX
- the screen is set from 140' to the bottom, which was plugged
at 240' (we hit salt water, so we had to cement back up to 240':-(
- good water pushed up to 110' - where it remains
- we have not placed any pump in the well as of yet
- we have 110 & 230VAC next to the well
- the "main problem" is that the well only produces 3 gallons
per minute! So we have to design around this problem.
Our best guess is that the well will constantly produce
3gpm of good water, but that's the best "rate of flow" that
we will ever get.
Here is my first thoughts for a pumping system:
1. Install a high quality small stainless steel submergible pump
and a small pressure tank at the well. Not sure which brand of pump,
size of pump, etc. The idea is to end up with a high quality submergible
pump system that will keep the 3 gpm flowing & last for five or so
years.
2. The submergible set-up above will keep a 2,000 gallon poly
storage tank filled by use of a float switch(s). An above ground "second"
pumping system will deliver a large volume of water as needed to the home,
yard, etc. - up to the amount of water available in the 2,000 gallon tank.
What I need is "SPECIFIC" recommendations as to the pump(s), tanks(s),
float switch(s), etc. I need make, model, etc. data to design this system.
Choosing the
proper horsepower(s), etc. of the pumps is a bit fuzzy for me:-)
I am currently looking at the Grainger catalog number 394 (page 2811)and the
Grainger site for pumps & switches, etc.
Here is the Grainger catalog in PDF:
http://www.grainger.com/Grainger/wwg...p?CatPage=2811
I have a similar situation. My well is 265' deep with the pump set at
240'. The static level is 75'. Sustained flow is about 2 gpm pulled
down to 220'. I have a 3500 gallon storage tank on a hill about 40'
higher than the top of the well, and 60' higher than my house. I just
use gravity feed from the tank to my house (no booster pump) and live
with the ~30 psi water. I'm in a very rural area and chose this
arrangement so I can get through several days of power outage.
For a top quality pump which will not distroy itself by pumping the well
dry I'd recommend one of the Grundfos SQE models. These have a processor
in them which measures motor current, voltage, speed and temperature and
they have adjustable setpoints to protect the motor. A 1/2 hp pump
should be sufficient for the head and flow you've discribed. They make a
nominal 5gpm model. Check the Grundfos website for performance specs
and how to calculate for your situation.
You can use a float switch with a power relay on the power to the pump
to keep the tank topped off, or if you like a little fancier setup and
more control get the CU100 controller for the pump. With that and a
4-20ma pressure transducer you can monitor the actual tank level, record
the cycling of the pump, and set the pump to shut off based on the head
the pump has to push. WIth that you'll never run the well dry. Thats
the setup i've just put in my well. Mine's a 1 hp 10gpm unit and the
whole thing including having a pump company install the pump was around
$2000. I did my own wiring, bought the controller seperate and got the
transducer on ebay. My old Grundfos stainless pump without all the
nifty protection lasted 9 years. I killed it by letting it run dry for
three days. Human error ;-(
You can certainly get cheaper pumps, but most of the cost is getting a
crew out to remove and install a pump, not the pump itself. Ok, you
could do that yourself too....;-)
--
Lou Boyd