Remote sensing of water holding tank levels (measuring contraption)

[JP]

Use an alarm system like the use on septic pump tanks. I just put in a new one,very simple to do.

[SF Man]

Oh. My mistake. I should have made it clearer.

- The well pump is nowhere near the house.

- Neither are the tanks (which are nowhere near the well pump).

PS: I didn't design it; I just bought it! :)

[SF Man]

I was wondering about that!

That's an interesting idea.

I presume we lower a weighted pressure sensor on the inside bottom of the tank, and, it simply senses the weight of the water on top of it.

From scuba, I remember every 33 feet was 15 pounds of pressure, so these tanks, being (roughly) 8 or 9 feet tall should have 1/4th that, or about 4 pounds of difference, empty to full.

Does that seem about the right calibration points?

[Dean Hoffman]

One foot of head in water equals about 2.3 pounds of pressure. Chart here:

[SF Man]

Interesting.

The Waterbug WB200 or WB350 seems to fit the bill, on initial inspection.

Since a well holding tank has got to be wet inside, key to operation is the sentence "Will not alarm due to condensation or humidity".

Seems to me, I screw the six sensors onto a weighted panel (or pipe) the depth of the holdin tank ... and then just lower that pipe into the tank and secure somehow.

The specs note that the wires can be 100 feet long, so that should be fine if I strategically place the main unit.

One intriguing sentence (on the Waterbug WB200) was "Can be used to detect ABSENSE of water (emphasis mine).

Seems to me, the absense of water is more interesting, to me, than the presence of water ... so I would think that WB200 unit would be the first to explore!

[SF Man]

Yet another interesting idea!

Yes, in fact I do have a 24-zone alarm system! I don't think I'd want the security company called every time I run out of water ... but I suspect that can be programmed to not call them for specific zones.

[G. Morgan]

Why 6 sensors? You would just need two on each tank, like how limit switches work in garage door openers. Or are you going for greater resolution?

You can use the sensors to trigger the timer to start a 'run' cycle when it gets below the lower switch (sensor). The top sensor would be a 'full' indicator, and shunt the pumps.

Are you going to use their annunciation unit? The sensors can be hooked to anything, like an alarm/home automation panel or PLC controller.

Yup, I've installed dozens. You can get really creative with them, they are versatile. I've used them to detect any water on the floor in a university chemical-storage vault. Some of that stuff in there was explosive if it reacted w/H2O.

I'm was surprised the head of chem.. dept. let me install the sensors all day alone in there. He said he was the only one with access and students are never allowed unattended. He gave me all kinds of warnings about keeping the door locked and the alarm on if I left, but ZERO instructions on what to do if I knocked a shelf full of volatile chemicals on the ground.

[SF Man]

The problem is that the holding tank isn't pressurized, but, the piping goes immediately to an adjacent 4-foot tall blue pressure tank and pump.

So, the water, to the house, is pressurized.

[SF Man]

My fault for not being clear.

The 'only' gravity part of the system is the four inch pipe that goes from the tanks to the fire hydrant, about 20 vertical feet or so down the hill (about 150 feet away from the tanks and on the other side of the house).

The rest of the system is certainly pressurized since that four inch outlet pipe almost immediately (within a few feet) branches off with what looks like a two inch pipe that goes to a pressure pump and blue tank that is almost right next to the large unpressurized holding tanks.

So, for all intents and purposes, all the house water, from the pressurizer next to the holding tanks to the house is pressurized.

[G. Morgan]

It can, it would not be programmed as a burglary zone, just a supervisory signal (or no CS report at all).

[trader4]

I would put the pressure sensor on a fitting on the bottom of the tank. Usually tanks have multiple outlets with some of them not used and plugged. Use one of those. I would not put it on the pipe feeding the house, as when the house pump kicks on it's going to effect the pressure, giving a false reading while it's running.

[trader4]

I don't see how they fit the bill at all. They are alarms that trigger when a sensor gets wet. You can hook like 6 sensors up to them, but they will just sound an alarm when it reaches any one of them. They are intended for applications like putting several sensors around your basement floor, so that if any one of them gets wet the alarm sounds.

Another big problem. Those sensors are intended for areas that are dry and rarely get wet. The inside of a tank is going to be wet with condensation, etc and even if you had 6 of them in there, they would probably all be wet enough to trigger the alarm.

I wouldn;t count on taking it to the extreme of the inside of the tank. I would take it to mean the condensation or humidity you would find on a basement floor or a laundry room.

And if one sensor is wet, it triggers an output or sounds the internal alarm. All that tells you is that at least one sensor is wet, not which one.

[trader4]

You don't need or want the holding tank to be pressurized. The weight of the water in the tank creates pressure and that is what you measure with one transducer. That pressure tells you the exact level of water in the tank.

[SF Man]

I asked three neighbors this weekend, and, ALL of them have the same mechanism!

They all have a block of brightly painted wood that is at the outside bottom of one tank (all tanks are in parallel) when the water is full; and it slowly rises, a few inches every few hundred gallons, until it's at the top.

The one thing different is that they all said their wells pump continuously ... so ... I must have a local problem with water flow.

I 'guess' there could be a three-light system, green being full, yellow being half empty, red being lower than that (or something like that), but, actual levels would be more informative.

[SF Man]

Do you know the brand you put in?

[SF Man]

Yet another interesting idea!

Yes, in fact I do have a 24-zone alarm system! I don't think I'd want the security company called every time I run out of water ... but I suspect that can be programmed to not call them for specific zones.

[SF Man]

I do have a home alarm system with many zones ... some of which (I think) are free ... so that's a possibility.

[SF Man]

Seems to me, if the work is going to be done to fit sensors, one may as well measure with greater granularity, than less.

[SF Man]

The thought was that the sensors are 'shorted' with water such that they remain shorted and continually show a short ... thereby triggering something (e.g., a light) which stays on as long as the sensor wires are shorted (by the water).

At least that's how it looked to me.

I thought about that too. The inside of a holding tank is very humid. Soaking wet humid, in fact. So, it really depends on how well the sensors reject super saturated air.

Hmmmm... that would be bad news. I 'thought' each sensor would be a different 'zone' so that the warning light would be a ladder of sorts.

For example, zone 1 triggers at, say, 1/6th the tank, zone 2 triggers at

2/6th, zone 3 at 3/6ths, etc., until zone 6 triggers at full.

[SF Man]

I like that idea.

It's simple, and linear.

Now to find the sensor ... I'll google.