Normal foot valve operation - allow backflow?

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garliceggs

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How does a foot valve normally operate? Is it just a check valve on the bottom of a well pipe? I see that they typically have a screen on them as well. Does that mean they replace the screen/point on a sand point?

I don't know if I have a foot valve or not, but if I did and I had water standing in my pipe all the way to the pump, would it drain back into the well at all? I would think that it would not. However, I've been told that a foot valve is designed to allow water to drain back slowly.

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Speedbump

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Strictly a one way valve and the screen really does nothing to speak of. It won't replace a well point or well screen, the holes are too big and not nearly enough of them.

bob...
 

garliceggs

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I'm not considering doing anything with a foot valve, I'm trying to figure out if I have one installed.

I'm inclined to think that I do not. I actually put the first point in this well and didn't use one then. But it has been replaced since then. And, if I remove the top check valve, the water doesn't exactly go rushing back into the well. It just seeps back very slowly.

If I have a plugged screen I would expect that sort of behavior, but I was told that a foot valve does the same thing. That didn't make any sense to me.
 

Bob NH

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It is unlikely that you have a foot valve on a driven point. You may have a check valve somewhere in the line between the well pipe and the tank, and it may be on either the inlet or discharge side of the pump.

If the check valve is on the inlet side of the pump, then the water pressure in the tank keeps the pump primed. If the check valve is on the discharge end of the pump then it is possible for a leak to let some air into the suction side, which can make it difficult to get the flow started.
 

garliceggs

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I know that I have a check valve on the top of my pipe on the inlet side of the pump (and nowhere else that I'm aware of).

I'm currently having problems getting any water out of my pump. When I remove the check valve from the line, the water drains down in the pipe, but slowly. Perhaps 5 feet per minute or so. Someone told me that's because there's a foot valve down there, but that doesn't make any sense to me. If that were the case, it shouldn't drain at all.

I think it's a clogged sand point and it just takes that long for water to go through it. And since that resistance is two way, it is at least in part responsible for me being unable to draw water out.
 

Raucina

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Sounds like a candidate for some target practice down the hole. See the OSHA safety notes elsewhere on this forum...
 

garliceggs

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I've had a couple of people suggest this to me already. However, I was naturally skeptical of such a proposal and after reading some of the posts on this forum I think I can safely state that I won't be performing this stunt myself nor would I allow anyone else to attempt such a thing on my well.

Besides, I don't really think that mineral buildup is my problem. I was pulling water out of this well last week and it stopped fairly suddenly. The point is inside a casing so I would be inclined to pull it up and replace it before trying anything explosive.
 

Speedbump

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Tell us what size this casing is and the size of the point. Also, how did you pull it and how did you put it back in.

bob...
 
R

Rancher

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You could try Speedbumps dry ice trick, it might work.

Put some chipped dry ice down the pipe, then cap the top. Ice will turn into CO2 and blow out the crud.

Rancher
 

garliceggs

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I haven't pulled anything yet.

The pipe is 1 1/4 in steel (in 5 ft lengths I think) and I believe the sand point is same in 3 ft length.

The casing is PVC and I would guess it's 4 or 5 inches in diameter.

I think we are going to try putting compressed air in the pipe to see if we can backflow the screen a bit.
 

Speedbump

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So, it's 1-1/4" driven point. What is the casing for? Is it a post hole (so to speak) with the casing to hold the sides open so you didn't have to drive the pipe so far? If not, explain what it does.

I don't think you will have any success with air. Once the mineral gets all over the screen, it's like concrete and it really has nowhere to go. There is sand all around it that is part of the concrete as well.

bob...
 

garliceggs

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A little history on the well:

Our soil has an abundance of large boulders. This was giving us lots of trouble when we attempted to drive the point in.

We had a guy come over with his backhoe and dig us a hole. I just placed the assembled point in here when we hit water and things were good.

The point ended up getting clogged fairly quickly so the process was repeated. This time I wasn't there so I can't verify the accuracy of everything here, but this is what I think happened:

Hole was dug
Pea gravel poured into the hole
casing placed in hole
pipe inserted into casing
- maybe pea gravel poured into casing
hole backfilled

The well has been working fine for 8 or 9 years this way.

This summer we started getting a lot of sand and I believe the water level dropped to the point where we were pulling air up too.

The water level has risen again and we were pulling water up, but a lot of sand also. This clogged up my pump. Last week we were able to draw water from the well, but could not build pressure past about 15 psi. We have another pump too (see https://terrylove.com/forums/showthread.php?t=16120
)

I cleaned the pump up, but now I can't get any water out of the well.
 

Speedbump

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I can see where boulders could ruin a Well Drillers day. The problem I see was putting Pea Gravel around that casing. That would let rain water and run off directly down to the point making the water your are using in your home kind of nasty. Had you backfilled with dirt, that wouldn't be a problem. If the point has been 9 years (I think you said) that's quite a while. It is probably plugged up pretty good.

If you do the same thing with the Backhow, try backfilling with dirt this time.

bob...
 

garliceggs

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I think they only put a couple of feet of gravel in there. The rest was the dirt they had pulled to make the hole in the first place. The reason they used the gravel was that the dirt was plugging the point. At least that's the way it was explained to me. Also, I wasn't around when they put this in the last time and my details may be off a little. I know the guy who did the digging so I'll ask him about the gravel when I see him next.

Anyway, there's probably 15 feet of dirt on top of the point. The water has always been fine and in fact we even had it tested.

It's also not being used in a home, but a cabin. A cabin that gets most of its use from Sept - Nov.
 

Speedbump

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I don't see how putting dirt around the screen could act as a well. Water only moves through sand, gravel and fractures in rock. Dirt does not qualify. I can see digging a hole to get by the boulders, but after that you should be driving the point the rest of the way to the water bearing formation.

bob...
 

garliceggs

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I apologize - I'm not making the same distinction between the terms "dirt" and "sand" that you are.

Also, bear in mind that I don't claim to possess much knowledge with respect to wells. It's entirely possible that mistakes were made and things were done wrong.

So the hole was dug and filled in again with the same material. I've been calling this "dirt" and "sand". I suppose the top three feet is more like dirt and rest is sand. Anyway the exception being that some amount of gravel was dumped in around the point - presumably to allow the water to get through without compacting the point with sand.
 

garliceggs

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I guess I'm asking for that advice now. I think that blowing air or even water back through the pipe will be have no effect.

We'll probably pull up the point. And then what? If it's plugged with sand, does this imply the well is shot? What recourse do I have here? You think I may be able to pump out enough of the sand to make it usable again? If I have to dig a new one, what steps should I follow? Are there other links here for that?

If the point is bad for any other reason - say mineral buildup, can I just replace it and put it back down the hole?

I suppose the answers to some of these questions depend on other factors.

My neighbors actually had wells drilled up there. The cost for this has been in the thousands and I'm not interested in spending that much on water for a hunting shack. Without other input, I'd probably repeat what we did and hope for another nine or ten years out of the next well.
 

Speedbump

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Your right about the other factors. But digging a hole and sticking the actual point in the dirt won't work. The point has to be in an aquifer which consists of sand/gravel. It must be clean. You can dig to get past the rocks, then put in a casing like before, but then beat the point the rest of the way into the aquifer. Test it every 5 foot joint with a hand pump until you get a good stream of water. Then hook it to your pump.

bob...
 

garliceggs

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It's difficult to imagine going 5 feet without hitting a large rock. This is why we gave up trying to drive the point in from the surface.

I know that you said this wouldn't work, but it did work. It's been working for years. So, what do you mean it won't work? That it's bound to eventually clog up?
 
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