It's me with another plumbing question. It's at a house that I am part owner of but which is 5 hours from my house. I am not there, but I know the approximate setup.

So there's this 800 gallon wooden water tank that stores water for a small house. The water is pumped from a cistern (supplied by a spring) and up hill to the tank, where it runs to the house by gravity feed. In principle, when the tank is full of water, a toilet tank type float rises and the arm shuts the valve, stopping the flow of water from the pump. The pump has a pressure tank.

In fact, most of the time the valve does not shut, and the water keeps pumping and the tank overflows onto the ground. The wooden structure that supports the tank about 20 feet off the ground is beginning to rot from the constant stream of water. Plus as we near the end of the summer, the cistern will drain dry, which probably means the pump will have to be primed and we may run out of water from excessive use. Not sure. Anyway, it's bad.

For now, we are letting the pump run long enough to fill the tank, then shutting off the pump manually by flipping the electric switch at the pump.

One plumber has been out twice and did not fix it. Another, who came highly recommended, came out and said the float was "loose." He tightened it and sent me a bill, but the neighbors told me the tank was already overflowing again the next day. I have a sometimes tenant who has replaced the valve twice. Most recently he installed a half inch valve in place of the 3/4 inch valve that was there. He's also, previously, replaced the old toilet tank size float with a larger one. Nothing has worked.

What are we doing wrong? Is there some interplay between the electric pump, the pressure tank, and the float valve that we are not taking into account? This system worked fine until about a year ago.

I think we have to find you a better float switch.
You also need possibly three levels. On, Off and Alarm.

What do you think?

The pressure tank probably isn't needed, but a regulator may be. Depends on the tower height.

An expansion tank may be. Not even sure about that one.

www.gemssensors.com is at least one manufacturer. Not sure yet what's suitable.

Somewhere in this system there should be a debris filter. Simple Screen.

Thank you, KISS.
I'm definitely ready for some help.

I don't know of a debris filter, though I'm all in favor of one. The water flowing from the tap in the house appears very clean, but sometimes tastes funny.

The tank could use a cleaning, and one plumber said the valve was dirty, but the tenant says, "I'm sure that the problem is not clogging since the valve I removed was as clean as the replacement. I think it must have something to do with pump pressure or the float in the spring box, but I don't have the expertise to figure out if that is the problem or to fix it."

A better float switch sounds like a good thing, but an alarm?

Pressure tank functions at times because it's possible to open and close some valves and have the water come directly from the pump to the house, skipping the tank.

Looked up expansion tank, but not sure what a regulator is.
Time for sleep now...
Thanks again.
Tank is about 20 feet up, on an old redwood stump.

Why hasn't the old toilet type float switch, which can suck up trash and not shut off with one more suitable for the job? (See image)
Cheers, Tom

Thanks, Tom!
So would any of these work? I really appreciate the pictures by the way.

Also, are these purely mechanical, or are they electrical switches? I think I see wires sticking out of the ends...

To my knowledge, there is no electricity at the tank. That's why I'm asking...

What Tom describes is indeed a switch that's used in sump pumps. The box floats on the surface and angles from horizonal to dangling and turns on and off the pump.

I too, am under the impression that the pump is turned off electrically from the float.

We need a better understanding of the system including any check valves and temperatures expected.

Just filling the tank to one level and stopping the pump. The pump should not restart until it reaches another level (hysteresis). For mission critical systems, a third sensor would be employed that could generate an alarm or failsafe. e.g. pump turns off forever until reset.

If the valve is mechanical or electrical, there has to be a filter/strainer in the inlet and possibly the outlet. See PERKO PKO 0493005PLB 493 SERIES INTAKE WATER STRAINERS PLUMBING SYSTEMS BOATING MARINE

I see your point that the pump needs to be turned off electrically. But I am pretty certain the float valve has no electrical component. I am writing to someone who has been up recently to double check. When I was last there, I looked for any wiring at the tank at all and found nothing.

Temperatures dip below freezing on occasion. Everything is outdoors and in northern California. Highs of about 95 degrees, lows of maybe 20, mostly 30 to 70.

Here is the order in which the water moves:
Spring, spring box (concrete cistern), water pipe going up hill, electrical pump and pressure tank in pump house near top of ridge, pipe through apple orchard to (non electric) tank on top of old redwood stump.

The pump fills the wooden tank and then supposedly shuts off in response to resistance from closed valve in tank--I thought.

So maybe the problem is in the pump house, not in the tank?
A problem valve or electrical switch at the pump?

This setup is rustic and basic... which you are probably getting by now.
Thanks for your continuing effort to help.

Yep. How else is the pump going to turn off. If the pump keeps pumping into a closed valve, the valve is going to fail.

If the float valve shuts off, this could indicate a high pressure to the sensor connected to the pump and shut the pump off. That switch would probably have a high differential pressure.

There is always the possibility of leaks in the line filling the tank to consider too.

EDIT: I guess I can see how a system like this could work. You could drain and turn off the feed to the tower and you would have water, but very little of it. The tower just increases the reserve.

Not sure what the height between the pump and the tower is. That's the height that matters. Not the 20'. That's only part of it.

How big is the spring cistern?

What type and size is the pump?

What size is the pressure tank?

Does the pressure tank have a pressure gauge?

What are the cut in and cut out pressures of the pump?

How big is the reservoir tank?

Is the float valve in the reservoir a ballcock type or a fill valve like a Fluidmaster?

Is the reservoir an open tank or does it have a cover?

What valve did the tenant replace and what is its purpose?

Is the failure of the float valve constant or is it intermittent?

Has anyone actually observed the float valve fail to stop the water flow to the tank, or is it just being assumed that since the tank is overflowing the float has failed? In other words you could conceivably have a leak in the piping inside the reservoir tank or at the connection to the float valve. Or you could have a bird or squirrel sitting on the float.

In theory your reservoir tank is no different than a toilet tank. A ballcock or fill valve should work and apparently has in the past.

Why do you have the reservoir tank? Does the spring dry up periodically or is there some other reason you need to store a volume of water?

I can think of no reason for having such a setup other than at some time in the past, before electricity, a manual pump was used to pump water up the hill to the reservoir tank to provide constant water supply to the house. I suspect that when electricity came along, someone just replaced the manual pump with a shallow well pump and tank.

Why not move into the 20th century, connect the house plumbing to the pressure tank. If you need to store a volume of water, get a bigger tank.

OK! If you need a mechanical float switch,(see image) we can do that also. Check them out at: MECHANICAL FLOAT SWITCH FOR FILLING OPEN TANKS SUCH AS CISTERNS OR STOCK TANKS.
Good luck, Tom

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Originally Posted by KeepItSimpleStupid

If the float valve shuts off, this could indicate a high pressure to the sensor connected to the pump and shut the pump off. That switch would probably have a high differential pressure.

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This is my best guess based on this conversation so far.

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There is always the possibility of leaks in the line filling the tank to consider too.

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Yes. We considered that idea and rejected it. There's no sign the pipe is leaking. The tank overflow is on a rather dramatic scale. We wouldn't miss that amount of water flowing out of a hole in the pipe.

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Not sure what the height between the pump and the tower is. That's the height that matters. Not the 20'. That's only part of it.

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I estimate the rise from pump to top of tank is 50-75 feet. No more. I think 50 or 60 is more likely. But I am not there and haven't measured it. The distance is another thing, maybe 150 yards. Rise from cistern to pump is another 30-40 feet, nearly straight up.

Hi Harold,
Thanks for taking an interest in my problem. I have answered your other questions below.

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Originally Posted by hkstroud

Is the failure of the float valve constant or is it intermittent?

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This is a really good question. It is intermittent, but mostly constant. If someone goes up there and monkeys with it, it appears to be "fixed." Whether they clean out the valve, tighten the float, replace the valve or whatever, it stops for a few hours, then reverts to running all the time. If I turn off the pump manually, then turn it back on, it always continues pumping after the tank is completely full.

I'm realizing this is not good for the pump... In fact, I think that's one reason there's a pressure tank at the pump, to give the pump a chance to cool off. Does that make sense?

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Has anyone actually observed the float valve fail to stop the water flow to the tank, or is it just being assumed that since the tank is overflowing the float has failed? In other words you could conceivably have a leak in the piping inside the reservoir tank or at the connection to the float valve. Or you could have a bird or squirrel sitting on the float.

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I think we've ruled this out. Tank has a raised cover with wire mesh that would keep out birds and small mammals. Insects can get in, but that's it. To my knowledge the pipe is not leaking and the amount of water would be hard for anyone to miss.

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In theory your reservoir tank is no different than a toilet tank. A ballcock or fill valve should work and apparently has in the past.

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Everything worked fine in the past. The pump shut off when the tank was full. I'm thinking a sensor at the pump has failed...

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Why do you have the reservoir tank? Does the spring dry up periodically or is there some other reason you need to store a volume of water?

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Yes. The spring barely flows by the end of the summer. Depending on water use, it's possible to run out of water in some years

Edit: Also, the power often goes off in the winter quite often. At that point it's great to have a water supply that comes by gravity feed from the tank. No electricity required...

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I can think of no reason for having such a setup other than at some time in the past, before electricity, a manual pump was used to pump water up the hill to the reservoir tank to provide constant water supply to the house. I suspect that when electricity came along, someone just replaced the manual pump with a shallow well pump and tank.

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There used to be a well and a manual pump by the house. I believe this cistern and pump were installed in the 50s or 60s.

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Why not move into the 20th century, connect the house plumbing to the pressure tank. If you need to store a volume of water, get a bigger tank.

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Now you are getting into issues of joint ownership and who wants to spend money on what. A bigger tank would need a new support system. The current tank is on top of a 20 foot stump, which would not support a larger tank.

Here are the rest of your questions. Thanks for helping. :)

How big is the spring cistern? I would estimate it's about 5 feet deep X 5 X 12 feet.

What type and size is the pump? Don't remember, sorry. Not an immersion pump. It's in a pump house up above the spring/cistern.

What size is the pressure tank? Can't say. It's about 16 inches in diameter and about 3 feet tall. Assume it's diaphragm type.

Does the pressure tank have a pressure gauge? Believe so.

What are the cut in and cut out pressures of the pump? Alas, I don't know. To get to the site is a 10 hour round trip, can't just pop up there to look. Up there, there is no internet...

How big is the reservoir tank? 800 gallons

Is the float valve in the reservoir a ballcock type or a fill valve like a Fluidmaster? I will try to find out.

Is the reservoir an open tank or does it have a cover? It has a raised wooden cover with 1/4 inch wire mesh around the sides. It seems well protected, but swallows roost on top of it.

What valve did the tenant replace and what is its purpose?
Its purpose is to open and fill the tank and shut off when the tank is full.

EDIT: If it will help diagnose the problem, I have a neighbor I can call up and ask to go over to try to answer these questions. Anything at ground level. He will not climb the ladder to the top of the tank...

Hi Tom,
This switch would be great if there was power at the tank running back to the pump house. To my knowledge there is not.

I was at the tank a couple of months ago with a contractor friend and we specifically looked for any sign of electrical wires or conduits. Nada.

The question that we seem to be down to is, what type of float valve do you have and how does it function? Can the pump pressure over ride it?

The valve Tom is showing is strictly mechanical. It stops the flow of water and the resulting pressure build up in the lines and the pressure tank stops the pump via the pressure switch on the tank.

Assuming that the float valve you presently have can be over ridden by the water pressure of the incoming line, suggest that you try lowering the cut off pressure of the pump.

Since the decay of the reservoir tank cause by the frequent overflow appears to be a concern, suggest that you drill a hole in the side of the tank and install a overflow pipe carrying the water away, just in case you have float valve failure.

Harold, except watering the orchard.

KISS,

I say let the trees go to the creek and get their own water. I know that sounds cruel but it's a cruel world and everything has to earn it's own living. What else do they have to do all day long?

Hi Harold,
To repeat, I'm pretty sure there is no pressure switch On the Tank.
That's the part that sort of mystifies me. Believe me, I looked for one.
I'm assuming for now that there's a bad pressure sensor switch at the pump.

Still waiting to hear back about type of float valve.
Lowering the pressure sounds like a good short term solution. It's worth a try anyway.

I REALLY like your idea for an overflow pipe to protect the scaffold.

Orchard does not normally get watered. :)
Nearest creek is more than a mile away and about 800 feet below top of ridge. Trees are old and unable to walk that far.

This is apple, sheep, timber, and pot country, in no particular order.
J

Nice point by everybody. I agree with Harold that the tank overflow needs to be directed. You still need to know if it's happening.

My best guess is that the pressure switch in the pump house is defective. The contacts will stick once and a while probably because they are pitted. That's why you have an intermittant operation. The longer the pump runs, the more chance there is of sticking.

The switch failure is causing the pump to run and is causing the float valve to fail.

Look at the system for possible future and current locations of debris filters. One looks pretty simple. It looks like a "T" with one side at an angle and just contains a screen.

Examine the contacts of the pressure switch for pitting.

Just to make sure that we are communicating, when we say pressure switch we are talking about the pump pressure switch located at the pressure tank or on the pipe between the pump and the pressure tank. You MUST have a pressure switch there.

I agree with KISS that pressure switch sticking may possibly be root of all the problems.

There is probably two.

One is in the inlet to the tank. It basically detects when the float valve closes and turns off the pump. This is the likely defective one.

The second is in the pressure tank portion. This maintains pressure for the system. In most cases, it's not used because the pressure is supplied by height.

So, I would envision a system in which two things can turn on the pump:
1. Low delivery pressure (To charge the pressure tank)
2. Low pressure to the tank. Signifying an open valve.

I hope this system has a pipe into the storage are and one leaving and I'd hope this system has two pumps like one in the pump house and one(?) in the house(s) itself.