I have a bored well (8" wide, water level 20 feet) that is not being used. Next year I plan on buying a submersible pump and installing pipe to my pond to keep the level consistent during the summer and fall months.
Any ideas on pump brands, piping considerations, etc?
This well has water at a current level 20 feet below the surface?
My well is ~650 feet deep and some times has water as high as 150 feet below the surface. But I put in a submerged pump at almost 650 feet. That way I have water even in the dry season. So you may want to try to measure the depth. A weight on the end of a string will work. You may want to rinse it with bleach first so you don't add any bacteria to the well.
My pump is a gould 1hp run by 220V through 10 gauge wire. The pipe is PVC down to the pump and black plastic to the house. This all fits in a 6" well casing with a pitless adapter. http://www.goulds.com/master.asp?id=3
What you need to find out is the depth of the well and capacity. I know the 6" well casing storage is calculated at 1.5Gal/foot so in 100' of water you have 150 gal storage. Then the recovery rate of X GPM is the real flow rate of the well.
The typical rule of thumb for pump sizing is up to 200' a 1/2 HP is OK, 2-450 3/4 HP and over 450 a 1 HP. It also depends on the static water level when pumping. If it's at 50-60' average thats the amount of head pressure the pump must overcome when running.
If you don't know the capacity of the well, and want to use this to fill the pond, water plants etc, just put in the submersible the correct depth (10-15' off the bottom) then set up a timer for the pump to run on intervals at a flow rate the well can support, as well enough to keep the level up to where you want it.
You will need a pump house for the expansion tank etc Also I recommend a low pressure cutout switch (in place of the standard on/off) on the tank in the event of a low level/out of water situation. this will prevent the pump from buring out.
As carl points out most folks use a pressure tank. This acts just like that capacitor, but stores water rather than charge. The idea is to minimize the number of times and duration that your pump cuts on and off since this is what wears out the pump. You run the output of the pump to the pressure tank and then to your load; usually house but in your case maybe a pond. A pressure switch is then installed as set to turn the pump on at a certain pressure and off and a higher pressure. On at 20 psi and off at 40 psi is common. Normally you will also have a pump controller and perhaps a pump protection system like carl mentioned.
My system has a 86 gallon pressure tank, a franklin electric controller and a pumptec protection unit. Its all 220V. The pressure switch turns on the controller which then starts the pump. The pumptec is wired in between the switch and the controller and senses a change in the current of the pump when it runs out of water. It then safely turns it off for a preset period of time to allow the well to recover.
You can get most of these parts at lowes or home depot. http://www.franklinelect.com/Prod_text/el_menu.htm http://www.waterace.com/tank.html
You may need some kind of level switch rather than a pressure switch since I would guess you are not worried about a contant pressure of the water supply. This would set the system up to atomatically top off the pond?
I have had my system for only about 1 year but it works great.
Assuming you have a constant water supply between 20 & 30' you can use a normal jet pump (above ground) with a single pipe, or if you need to go to 50-60' a two pipe jet pump system with an ejector at the bottom of the well.
The single pipe system 1/2 HP with a small expansion tank is $250 plus pipe in the well so probably under $350. Or if you need to go to a two pipe system with a 3/4 HP unit and tank this will run about $450 or so.
The submersible 1/2 hp two wire (no control box needed) with tank, pump, wiring foot valves etc. will probably cost you about $600 all done.
If you want to look at all the various pumps check out web page and type in water pumps in the search..
As mentioned above a method for automatic level control in the pond - a cheap way is to mount a toilet valve in the pond, or you can also get a similar setup for cattle water tanks with a float attached to a brass valve.
Well, Buck.....this is a pretty straightforward application and you've had some real good advice profered here. Actually, submersibles do not work all that well in shallow settings. Over-pumping from the lack of total head is the culprit. If the pump pumps from, say 25-30 feet, all you have for head is the lift and whatever friction losses you accumulate in the piping that goes to the pond. Subs do a lot better if they are pumping against head, either from tank pressure or from lift out of the well. A pound of tank pressure is equal to 2.31 feet of lift. One of the ways we protect subs from over-pumping is to use a flow control valve on the discharge. A flow control looks just like a coupling but has a rubber washer in it which allows only a specific flow to go by. If you buy a sub that pumps 5 GPM, then you install a flow control valve that ONLY lets that much go by. That way, you can match pump capacity to well capacity and keep from sucking it dry. A flow restricting valve is cheap insurance and solves a lot of problems. Your application is well within the capability of a shallow well jet pump, so you could go that route. Freezing is a bigger problem with jet pumps, and so is priming, and they really need to pump against some tank pressure, which in your case would be a waste of HP and the unnecessary expense of a tank. The absolute rock-bottom amount of machinery would be a sub, with a drop pipe and a Dole flow control valve; a piece of pipe and a buried wire to the pond and a float switch. When you shop for that sub, BE SURE that you select on the basis of very low pumping head, otherwise there'll be trouble with over-pumping and upthrust will destroy the little bitty turbine bowls that make up the pumping element.
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