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I have cistern which is filled either by truck or pumped from the lake. To connect to the cabin, there is a pipe with a foot valve at the bottom, and a pump with a pressure tank at the bottom of the cabin.

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My setup is a bit different since we don't have a basement, and the pump is closer to ground level so there is around a 5 foot (1.5 m) height difference between the foot valve/bottom of the cistern to the pump.

In the current setup the foot valve works perfectly, you prime the pump at the start of the season, and it doesn't lose prime. I want a valve which at I can open without going into the cistern to drain the water at the end of the season.

The problem that I am trying to solve is during winterization of the cabin. We can drain all the lines inside using compressed air, but to drain the suction line (from the pump to the foot valve), we remove the foot valve so it all drains. Is there a better way of doing this?

I looked up how it's done with submersible pumps, and it appears that there is a snifter valve paired with a drain back vavle (also called water outlet, "bleeder valve" or "Bleeder Orifice". There are two versions:

Copper (with a ball):

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As a pump turns on and builds water pressure, the orifice is forced closed with a ball. When the pump shuts off, pressure drops and the orifice is opened, allowing water above the orifice to drain out.

There is also a rubber version:

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Provides fast water bleed capacity through its large orifice opening when pump shuts off Orifice completely closes when the pump is running and prevents loss of pumping volume

How do these work and would they work in my case?

From the sub pump version, I believe they need a Snifter Valve which allows air into the line.

My understanding, in theory in my case, if my plumbing is air tight, when the water pump stops and the tank is pressurized, not much water would drain back out of the drain back valve.

In practice, when I installed the foot valve with a small gap (I didn't warm the pipe up before putting in the barb), it was leaking and the pump would lose prime every 3 minutes (since air might be entering from a joint in the buried pipe?). I'm afraid if I installed this drain back valve, I would have the same problem potentially as I might have an air leak somewhere.

Are there other alternatives? One idea is a pressure blow off valve right after the foot valve. This way I could add a string line and pull it open to drain.

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The other ideas I have seen is connecting a fishing wire to the foot valve so you can pull it open from outside but it seems sketchy. This is explained in this video: https://www.youtube.com/watch?v=PGV0BSPDPbQ but the idea is he glues the foot valve nut to a washer with a hole which is connected to a fishing line:

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The other idea is a ball valve which is spring return ball valve which is normally closed and doesn't have a too tight spring. This also seems unideal as it will be submerged.

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1 Answer 1

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Stainless steel cable, sufficient pipe on the foot valve to reach out the access hole, attach the cable to the pipe near the foot valve, yank the foot valve up without having to enter the tank, and remove it. Not some hokey foolishness of tripping the valve. And when the foot valve eventually fails - hey presto, you don't have to climb into the tank to replace it.

The submersible pump has a pressure line out of it, and the pump is sitting in water and always primed. The foot valve is a suction line, and the pump loses prime if it empties - which is why leaks will work for the one and won't for the other.

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  • Thanks! So the cistern is only 4 feet deep so not hard to change the foot valve. The pain for me is that I would need to empty it, and refill it back 3/4 for winter storage. Commented Apr 3, 2022 at 15:48
  • Problem is that the pipe which is connected to the cistern is molded into the concrete, and has a 1" barb at the bottom. I put a small 1' long pipe which is then connected to the foot valve. I could put a longer flexible pipe which can be pull up with stainless steel cable, but that would add 4-5 feet on the suction line. Do you think that would be bad for the pump? I'm running a 3/4 HP jet pump with a tank and the line is around 8 feet or less to the foot valve. Commented Apr 3, 2022 at 15:48
  • These are trivial distances for pumping water (8 .vs. 13 feet of 1" pipe), and the foot valve will presumably still end up only as deep as the bottom of the tank, so no additional vertical lift. I'd expect it to be un-noticeable, unless the foot valve on a longer pipe does not want to stay down, which is likely a matter of working with the natural bend of the pipe when you connect it, or attaching a weight if it wants to be stubborn. When this pump dies, think about replacing it with a submersible in the tank.
    – Ecnerwal
    Commented Apr 3, 2022 at 15:57
  • Thank you, that makes sense! Problem is my family has 2 other jet pumps w/ tanks sitting in their basement so likely it will be a while before we go to submersible. Commented Apr 3, 2022 at 16:05
  • Another idea I had, if i didn't want to add the resistance of the 5' of 1" pipe: add a T from the foot valve, and have a pipe come up with a valve at the end which is accessible from the surface. I can pressurize the line with air then open the valve like I do for any other tap, and wait until all of the water escapes. Thoughts? Commented Apr 3, 2022 at 16:18

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