Old well

[Whatnot]

I have an old well on my property that I would like to put back into service for irrigation.
It has been a while since I looked at it but don't think the casing was in good condition. Is it possible to put a new casing inside? If so, what is the proper way to seal around the new casing?

The well is only 30' deep and was at least 6" diameter. Last time I looked, water was sitting around 10' below ground level. I have not tried pumping from it yet to see how much it will drop. I only need around 3 gpm and do not need much pressure. 20 psi at 3 gpm should be plenty for what I need. What would be the best pump to use for that? I am looking for the most efficient because it would run pretty much continuously.

 

[Valveman]

If the hole is still open you might be able to put a 4" liner in that 6" casing. A little gravel pack between the 4" and 6" would be best, but the 6" casing is what needs to be sealed to the earth.

A 10GS05 is the smallest pump you can get, and it will want to pump 14 GPM from 10' and 20 PSI. You will need to throttle it with a valve to make it only pump 3 GPM. Or you can use a PK1A to control the pump and only run 3 GPM as needed.

 

[Sponsor]

 

[Whatnot]

Is there no way to get it sealed to a new inside pipe? I am not sure there is enough left of the 6" for that to work.

What kind of wattage would that pump be drawing at 3 gpm?

 

[Valveman]

A 1/2HP submersible will draw about 1000 watts.

Post a picture of the well head.

 

[Reach4]

Franklin AIM manual shows a 1/2 HP 240 volt motor with a control box that includes both a start and a run capacitor at 655 watts.

 

[Valveman]

680 watts is rated input. 1050 is service factor, which is what it will be drawing.

 

[Reach4]

Franklin AIM manual shows a 1/2 HP 240 volt motor with a control box that includes both a start and a run capacitor at 655 watts.

Not if he throttles down to a lower flow.

 

[Valveman]

Not if he throttles down to a lower flow.

Still depends on the brand of pump. A 10 GPM Pentair will not draw lower amps with reduced flow. But yes a good Grundfos pump throttled to 3 GPM would only draw about 600 watts.

 

[Whatnot]

I will try to remember to take a picture. I am only there once or twice a week usually.
I found some 24v DC pumps that are rated at the flow I want and are around 100 watts.

 

[Valveman]

Post the model or spec sheet on the pump. It is not likely a 100W pump wuill lift from 10' and deliver much pressure.

 

[Whatnot]

I don't need pressure at the discharge point.
There are a lot of different options. This one is a lower pressure model https://www.sunpumps.com/Photo/335?d=7/20/20186:22:27AM
Most others I saw are up to 100 PSI/230' head but those use more wattage for the flow I need.
It looks like another nice feature of this type pump is I can just vary the voltage to adjust flow and use less power over restricting it.

 

[Valveman]

No you do not want to restrict one of those kind of pumps. If you are just filling a storage tank and don't need any pressure it should be fine.

 

[Whatnot]

I just opened up and there is only casing for about the top 2 feet. Then it I'd just sand wall. It appears to have originally been a dug well. There are flat stones in a circle about 2 feet diameter. Someone must have filled in around some sort of pipe that is now gone.

I think there used to be a windmill over it with a piston pump in the well.

Is there a way to salvage the well?

 

[Whatnot]

Pic.

 

[Whatnot]

Looking down inside.

 

[Valveman]

If you can get at least 4" casing and screen or perf down the well, you could pull out that 2' of steel and cement the top 10' or so.

 

[Whatnot]

How much of the casing should be perforated?
Is schedule 40 PVC ok to use? That steel pipe is 5" ID at the top but larger below the top part. The hole down below looks like it is probably over 6" but it is not straight.

 

[Valveman]

With 4" ID casing I would use 20' of .035 perf with a 12' stick of blank up top, and cement as deep as much of the blank as possible.

 

[Whatnot]

What exactly is .035 perf? Google searching doesn't really work. Mostly just finds SDR 35 pvc.
It that .035" slots cut in PVC? If I search for perforated I just find it with round holes that are fairly large.

I see they make PVC that is labeled for well casing. Is that required or can regular PVC be used? I am not sure if anywhere locally would carry the stuff labeled for well casing.

 

[Reach4]

Search for slotted well casing or
slotted screen.