Need advice regarding an unusual application

[blshaw45]

I am not a mechanical engineer nor otherwise any kind of professional regarding water wells, pumps our anything related thereto. I thus hope that some members of this forum can offer some advice on an important application, discussed below.

I represent a mountain-side residential community that has an 800-foot deep water well that will eventually be shared among about a half dozen homes (although at present only 3 homes are hooked up). The wellhead is at an elevation of about 2830 feet and there is a 1700 gallon storage tank at an elevation of about 3070 feet. A 3hp pump in the well delivers water to the tank via a buried "feed" pipeline running approximately 1200 feet uphill through the woods. The pipe enters the tank above its high-water level and water "falls" into the tank (thus precluding any siphon affect, although there are also check valves in the well's casing). There is also a smaller pump in the tank near its bottom that delivers water to a co-located pressure tank. A "supply" pipeline connects the pressure tank to the currently-participating homes, all of which are fairly close to the tank.

A new home is under construction at about the same elevation as the wellhead and within 325 feet of it. One way to provide water from the shared system to the new home would be to extend the present supply line downhill, but this would require digging a trench approximately 1400 feet in length and cutting pavement to get under a roadway.

Another option for supplying the new home is under consideration. Specifically, we think that we could install a "T" connection in the feed pipeline at the wellhead. There’d be a shut-off valve at the T and a new 325-foot pipeline would be laid from there to the new home. Since my calculations suggest that the pressure at the home would be over 100 psi due to the ~240 foot head above, there’d be a pressure reducer in the home and a backflow preventer.

The last component of such a system would be an elbow on the feed pipe where it enters the tank and an extension from the elbow to a point below the tank’s low-water level. This would allow the new home to siphon water from the tank.

I have attached diagrams that illustrate both the present system and the proposed system.

Can anyone think of a reason why this latter option will not work or should be avoided?

Thanks in advance!!

 

[Chucky_ott]

Maybe I'm missing something but which pump will supply water to Bonnie's house? The submersible in the well is controlled by the float switch in the storage tank. A call for water by Bonnie will not start that pump.

 

[Sponsor]

 

[Chucky_ott]

Never mind my previous comment. I missed the part where you modified the pipe in the 1700 gallon tank to create a siphon and use that tank as the water source.

 

[Valveman]

It should work as you are thinking. However, it won't take much of a leak in the pipe up top to loose siphon. It would be better to draw and fill from a lower bung on the tank if possible.

 

[blshaw45]

Never mind my previous comment. I missed the part where you modified the pipe in the 1700 gallon tank to create a siphon and use that tank as the water source.

Correct. New home fed entirely by gravity.

 

[blshaw45]

It should work as you are thinking. However, it won't take much of a leak in the pipe up top to loose siphon. It would be better to draw and fill from a lower bung on the tank if possible.

Thanks valveman! I agree that a leak would be more than a little problematic, but since everything is buried, the risk is pretty minor (knock on wood). Of course, there was that 5.1 earthquake here a couple of days ago.....

BTW, others here might be interested to know how the float switch in the tank signals the pomp in the well to come on. Originally, a wire was buried with the feed line. We lost continuity on that a few years ago. We suspected a bad underground splice (getting a reel of wire 1000+ feet long was probably not possible or practical, so there must have been at least one splice somewhere) but unless we dug everything up, we would never know. So a radio system was installed, but it proved unreliable when all the leaves on the trees were out. So I designed and implemented an IoT (Internet of Things) system using cellular. Works like a charm, and I can monitor and control everything from anywhere using my phone or my computer. If anyone here is curious about that, I'd be happy to share the details.

 

[blshaw45]

It should work as you are thinking. However, it won't take much of a leak in the pipe up top to loose siphon. It would be better to draw and fill from a lower bung on the tank if possible.

Hi again valveman. Just curious: are you an engineer of any flavor?

 

[Ballvalve]

Thanks valveman! I agree that a leak would be more than a little problematic, but since everything is buried, the risk is pretty minor (knock on wood). Of course, there was that 5.1 earthquake here a couple of days ago.....

BTW, others here might be interested to know how the float switch in the tank signals the pomp in the well to come on. Originally, a wire was buried with the feed line. We lost continuity on that a few years ago. We suspected a bad underground splice (getting a reel of wire 1000+ feet long was probably not possible or practical, so there must have been at least one splice somewhere) but unless we dug everything up, we would never know. So a radio system was installed, but it proved unreliable when all the leaves on the trees were out. So I designed and implemented an IoT (Internet of Things) system using cellular. Works like a charm, and I can monitor and control everything from anywhere using my phone or my computer. If anyone here is curious about that, I'd be happy to share the details.

Very interesting to me as I designed and installed a nearly identical water system for a mountain subdivision of mine. About the same elevations also. As valveman said, I just pump into the lowest bung on the tank and water runs in there. And out also; I went a large step away from yours, and did not install any feed pipe. The delivery pipe and the feed is the same, users just tap out of the one line to the top of the hill. Every one down hill gets gravity feed and some need pressure reducers and others a tank and pump. 160 psi at the well head. I sold the project out and never installed a float control, rather I used a timer and the overflow went into an adjacent pond. By now I suspect there is a radio or internet control on the system.

likely best to not make a siphon as mentioned, as feed will be lost when the tank goes dry and you will need to prime it. Your proposed drawing is how all my homesites are serviced with the feed and service pipe one and the same.

 

[well hook up]

It should work as you are thinking. However, it won't take much of a leak in the pipe up top to loose siphon. It would be better to draw and fill from a lower bung on the tank if possible.

Valveman,
I am the homeowner that blshaw45 is referring to when trying to figure out a way to hookup my home to obtain water from the community well. Might you comment on this proposed test system to see if the scheme B will work?

It might be pretty easy and cheap to set up the basic system right beside the wellhead, before any pipe is laid. A “T” could be installed right above the well casing where the pipe comes up and out, add a shut-off valve and a pressure reducer and test it right there. Quick and cheap. Just verify that it could fill a bucket from it.

 

[Valveman]

Hi again valveman. Just curious: are you an engineer of any flavor?

Lol! Not technically.

 

[Valveman]

Valveman,
I am the homeowner that blshaw45 is referring to when trying to figure out a way to hookup my home to obtain water from the community well. Might you comment on this proposed test system to see if the scheme B will work?

It might be pretty easy and cheap to set up the basic system right beside the wellhead, before any pipe is laid. A “T” could be installed right above the well casing where the pipe comes up and out, add a shut-off valve and a pressure reducer and test it right there. Quick and cheap. Just verify that it could fill a bucket from it.

What is proposed will work. I also think you could put the well pump controls at the well, and tee after that to the storage and and lower house. Something like in this drawing.