Sand point connected to shallow well pump. Possible?

[stormlight]

Hello, If you drive a Sandpoint down into the ground there is no foot valve. Since you do not have a foot valve is it possible to hook up the sandpoint to an electric pump for irrigation. Or will the pump always loose prime with out a foot valve.

Is the answer to this to put a check valve on the output side of the pump so the suction side of the pump in theory will never looses prime?

If my guess is correct why would one not do this with a standard drilled or augured well and instead us a foot valve. Whats the benefit of using a foot valve in a non sand point well?

thanks

 

[Reach4]

If my guess is correct why would one not do this with a standard drilled or augured well and instead us a foot valve. Whats the benefit of using a foot valve in a non sand point well?

A check valve, which a foot valve includes, at the bottom keeps the pipe full of water.

A shallow well can keep the pipe almost full with a check valve up top. But if the water is farther down, the water above a submersible would just vaporize in the pipe. When the pump started, the water would come up and there would be a bang. Plus there would be a wait for water.

 

[Sponsor]

 

[stormlight]

A check valve, which a foot valve includes, at the bottom keeps the pipe full of water.

A shallow well can keep the pipe almost full with a check valve up top. But if the water is farther down, the water above a submersible would just vaporize in the pipe. When the pump started, the water would come up and there would be a bang. Plus there would be a wait for water.

Ok, but since a sand well point has no foot valve at the bottom how does it not have these same problems you describe above? What am I missing ?


Also, where is the proper placement for a checkpoint valve on a sand point. On the suction side before the pump or on the exhaust side after the pump?
Thank you

 

[stormlight]

I should say this is in reference to a 25 foot well.

Thanks

 

[Reach4]

At 25 ft down to the water surface, water can stay liquid at the reduced pressure. If the water surface was 35 ft down, you would have a vacuum at the area in the pipe just above the water that has no liquid water. Under those conditions, you could not use a suction pump.

If you could put a check valve at the bottom, that would be better. Then the pipe would not have reduced pressure inside, and would not suck air through a possible tiny crack at a joint. Water may not go through that crack but air might.

 

[stormlight]

I think I’m throwing to many things at this thread, Sorry. It’s 8 foot to the water from surface and 25 foot from surface to the check valve. This was just for reference.

I guess my main questions/points that need clarification in my example of surface to water being 8 feet is:

1. Are foot valves are not needed when your surface to water measurement is around 8 to 10 feet? (Instead you can use a check valve)

2. What side of there pump do you put a check valve when there is no foot valve.

3. At this range if you had a choice would one opt for a foot valve at the bottom or check valve at the top? Why?

Thank you to all.

 

[Reach4]

I had thought this had drifted in the direction of an academic discussion. My comments on this thread are not based on experience.

1. No, but they would be better if practical. Not practical with a sand point.
2. Normally input.
3. foot valve due to easier priming. Also because it keeps higher pressure water in the pipes. This would mainly make a difference in the case of micro leaks or dissolved gasses. If your pump was "self priming", that could overcome some imperfections I think.

 

[stormlight]

I had thought this had drifted in the direction of an academic discussion. My comments on this thread are not based on experience.

1. No, but they would be better if practical. Not practical with a sand point.
2. Normally input.
3. foot valve due to easier priming. Also because it keeps higher pressure water in the pipes. This would mainly make a difference in the case of micro leaks or dissolved gasses. If your pump was "self priming", that could overcome some imperfections I think.

Thank you, again. My question now is how? Say I have a well and it has a foot valve. If something gets caught in the valve and it stays open the water falls out of the foot valve and the pump loses prime. On the other hand with a check valve near the pump i could see the check valve keeping the pumped prime for a few seconds when its turned on. However after a second woldnet the pump hit a big airgap because water leaked out of the sand point causing an airgap in the suction pipe?

To combat this should the check valve be installed at water level to reduce airpockets?

 

[Valveman]

You can't use a foot valve on a sand point. The best you can do is install a check valve as close to the top of the sand point as possible. A check valve up top will keep the pipe full of water the same way as putting your finger over a straw full of ice tea. You just can't have any air leaks in the sand point, which you can't have anyway or the pump would suck air as well.