Will this idea work to backflush a "shallow well" ?

[super55]

My parents house has a 2" 160' "shallow" well that I would like to see if I can increase the flow rate on. I use the term shallow because it's a 45 year old well that runs off a 3/4 hp shallow well jet pump. The well is artesian and will flow about 3 gal a min on it's own without a pump.

They had an irrigation system installed some years back for the lawn but never really got desired results due to lack of flow rate from the well and I believe the pump may be having issues drawing the water up. I asked my dad if the flow has decreased over the years and he says it's about half of what it used to be. He used to be able to run a single sprinkler off the well alone without any assistance from the pump now it can't even get the rotor head to turn.

I was thinking of trying and backflushing the screen by hooking compressed air and pressurizing the well to force the water back down the well to blow out the sediment from the double screen and since it's artesian it should self prime itself without any troubles.

Has anybody ever done this before or have any advice? In theory I think this may work. I would hate to make a multi-thousand dollar mistake here. So any other ideas or concerns are welcome.

 

[Stimw]

I think you would be better off to rent a 2" gas pump and connect it to the 2" well pipe and try pumping the heck out of it! The gas pumps can have a volume of 25 gpm or more and should help flush it out.
It probably has a problem with sediment and pumping would purge the sediment.

 

[Carl_NH]

Stim has a good point as the high GPM pumps usually have a bellows set up but remove the check valve to allow the bellows to push/pull like a plunger to clean the screen and debris - since you have postive flow this will rinse the screen off. This would allow the artesian flow to continue but push/pull on the screen more gently than a "fracking" with air.

Your idea to back flush would need a considerable volume of air like a commercial compressor - thats not a bad idea either but it its flowing 3 GPM you will need to do a pressure then release cycle to clean out the screen.

The trash pump with the bellows removed may do the same thing at lower cost.

Unless its really badly plugged I cant see the harm in either method, but it will take some time to clear once you do this.

 

[super55]

I really like the idea of utilizing a trash pump as you guys mentioned. My first thought was where I was going to get water from to push back down the pipe but i have a 55 gal. barrel that I could use as a reservoir. The craftsman air compressor I was thinking of initially using can only push 6.2 cfm at 40 psi and then 5.2 at 90. I know I won't get a lot of volume with the compressor but hopefully it will be enough to break any sediment off.

Ok I think I have developed a plan of attack.

1. Hook up trash pump to well on inlet side and attempt to move large volume of water to pick up any debris or sediment that may have passed through the screens but has since settled on the screen tip due to 45 years of use and high iron content.

2. Hook up air compressor to well and frack and bleed well several times to help remove any scale or debris that might be restricting flow from the outside of the screen.

3. Now hook the outlet side of the trash pump to the well and flush tip with a larger amount of water to help move the sediment away from the tip back into the sand.

4. Have a few beers or go golfing to allow time for the sand that may have been pushed away from the screen to move back in.

5. Hook well to inlet side of trash pump and move copious amounts of water to clean out casing one last time before connecting to the household lines.

I think this sounds like a pretty solid OP-Order, Besides this sounds like the perfect excuse for me to tell the wife I need a trash pump.

 

[Egon]

Could you describe how the well is set up. Ie-- suction pipe size and depth?

Check valve?

Why not pull the suction line.

Consider iron deposits that have scaled off the screen?

 

[super55]

Could you describe how the well is set up. Ie-- suction pipe size and depth?

Check valve?

Why not pull the suction line.

Consider iron deposits that have scaled off the screen?

It's a 2" galv. pipe that is 160' feet deep. That has from what my dad believes is a 4' screen well tip on it much the same you can find at home depot or lowes. There is no suction line inside the well pipe because it is an artesian well and no lifting is necessary. The pipe is then directly reduced to a 1" fitting in order to connect to the 3/4 hp jet pump. There is no check valve in the system as far I know.

I agree with you on the iron deposits. In all reality I really think that is the culprit of the reduced flow. Only problem is the location is 160 feet underground in a naturally pressurized system.

 

[Stimw]

I don't think I would push anything back down the well for fear of contaminating the well or the aquifer.
Another thought that came to me, around here, 20 or so years ago artisan wells had 20' standing head pressure. Because so many wells have been put down that has dropped pressure to zero at times and people think their well has dried up. An honest well company will just sell them a primary well pump. (a lot of artisan wells fill an areator and then pump to the house not using a primary pump)
You might just have a problem with too many wells pulling water from your aquifer. ?????

 

[radioman]

first of all - are you sure the galvanized pipe didnt corrode to a point where its half size of what it used to be? second, did you pull the foot valve yet and check for sediments? backflushing it thru the pump pipe will hurt the foot valve, after all its designed to keep piped primed. third, an expensive test but did you try using another pipe going into the well and to pump as a test to see if original pipe is closing off?

 

[rswyan]

It's a 2" galv. pipe that is 160' feet deep. That has from what my dad believes is a 4' screen well tip on it much the same you can find at home depot or lowes. There is no suction line inside the well pipe because it is an artesian well and no lifting is necessary. The pipe is then directly reduced to a 1" fitting in order to connect to the 3/4 hp jet pump. There is no check valve in the system as far I know.

Interesting ....

I agree with you on the iron deposits. In all reality I really think that is the culprit of the reduced flow.

Ahhhh .... this I'm familiar with ....

Eight years ago we lost our pump due to iron sedimentation at the bottom of our well (which is not artesian) - the iron had filled the bottom of the well and completely coated the intake of the pump and clogged it up. Burned the pump up.

Only problem is the location is 160 feet underground in a naturally pressurized system.

We had the local water company we buy our softener salt from come out and "bail" the well.

They pulled the pump and used a bailing device (a couple foot long tube, with a flap trapdoor bottom) to pull out all the loose sediment at the well bottom. After doing so and replacing the pump (upgraded from I think a 1/2 HP to 1 HP) we were golden .... for another 8 years ....

I just called them a couple of days ago to come out and do it again, as I noticed that with heavy, continual water usage (washing of the driveway) the well eventually gets to the point where the recovery rate drops off sharply. Cost is around $350 or $400.

What they didn't do the last time was "brush" the well .... as they didn't have the brush or the rig to do it - but they suggested that if after bailing it and running for awhile if there was still a recovery problem, we'd need to contact another company that could "brush" it. Apparently this loosens the iron off the well bore that may be limiting flow into the bore.

This is on a 4" or 5" well that is around 300' or 400' deep, IIRC.

If you have a problem with iron sedimentation at the bottom of the well, then IMO, you probably need to remove the sedimentation to restore performance. I see "backflushing" as a less than ideal solution.

Try Googling "brush and bail" ....

 

[Egon]

Sounds like dropping a camera would tell the tale. they are rentable.

You could drop a spagetti line down to the bottom and acidize?