I am helping a friend protect the pump for his above ground cistern by adding a water level sensor. It is actually 2 cisterns under their deck connected together via about a 3" pipe. To keep it simple I am suggesting adding a saddle Tee and with a riser pipe attached (see drawing) and sensing the water level in it. They generally draw on one cistern at a time by closing one of the valves. There is very little head space between the cistern top and the deck so inserting anything long in the riser pipe is not easily done. I expect to use a 1.5 to 2" diameter riser pipe. To keep maintenance easy I want the switch to handle the 125 VAC direct to the pump. I have looked into optical and non-contact sensors but I would like to get opinions from TBN first. Any suggestions are welcome.
Sensing water level in cistern
- Thread starter MillWeld
- Start date
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chim
Elite Member
Without knowing more about the setup, I'd drop a sump pump with its own switch into one tank and call it good. Plug the pump in or have it hooked up through a switch when you want water. This is assuming the pump is for watering flowers, etc. and won't be dead-headed. (Or there's a pressure switch to kill the pump)
If it's a pump that needs to keep a system pressurized, drop one of these in the one cistern:
Everbilt Tethered Float Switch with Piggyback Plug-TFS13D161P1 - The Home Depot
Either way, no water and the pump won't run. No reason to tap a tee into the equalizing line.
If it's a pump that needs to keep a system pressurized, drop one of these in the one cistern:
Everbilt Tethered Float Switch with Piggyback Plug-TFS13D161P1 - The Home Depot
Either way, no water and the pump won't run. No reason to tap a tee into the equalizing line.
CincyFlyer
Veteran Member
Yeah, that seems cheap and easy, my two favorite things!
Valveman
Platinum Member
You can sense water level till the cows come home. What you really need is something that shuts the pump off if/when it runs dry.
Dry Run and Rapid Cycle Protector Cycle Sensor for Submersibles and Jet Pumps - YouTube
Dry Run and Rapid Cycle Protector Cycle Sensor for Submersibles and Jet Pumps - YouTube
rm4usall
New member
I use Franklin Electric Pumptec in my cistern. It was originally installed in my (now failed) well because the pump pushed more water than the well could produce, so this device would shut off the pump when the "well ran dry" which was everytime.
Now it's in my cistern to protect the pump in case I let the water level get too low.
Pumptec Family | Residential/Light Commercial | Drives & Protection | North America Water | Franklin Electric
Don't know if this is what the OP wants, but thought I'd mention this because it was mentioned - Brian
Stimw
Elite Member
A simple water level gauge is what they use in motor home water tanks.
It has 4 simple buttons at different levels, when the water is over the button it reads on a light and uses 4 lights with a push button to read.
They operate on 12 V and could be mounted on a piece of PVC pipe put in the tank.
It has 4 simple buttons at different levels, when the water is over the button it reads on a light and uses 4 lights with a push button to read.
They operate on 12 V and could be mounted on a piece of PVC pipe put in the tank.
JPRambo
Platinum Member
Drop a wired float in the tank to close circuit when hanging above water to start pump and to open the circuit when floating to shut off pump . Use another to hand lower than the first hanging position as an alarm to check the pump.
PILOON
Super Star Member
Most 'sump pumps' use a float type switch that starts the pomp when a high level is reached.
Costs +/- $20.00.
That same float switch can be re wired (via a relay) to shut off a pump as well with a bit of mechanical installation tricks.
(Like attach it high and use a relay that opens when the float switch closes)
Costs +/- $20.00.
That same float switch can be re wired (via a relay) to shut off a pump as well with a bit of mechanical installation tricks.
(Like attach it high and use a relay that opens when the float switch closes)
prichard
Veteran Member
One of these, pump plugs into it and done. Water Source Piggy Back Float Switch for Sump and Sewage Pumps at Tractor Supply Co.
The cistern is used for watering a garden. The pump is turned on manually via switch; if they fail to notice a low level in the tanks the sensor will cut the power. The pump is already in place (external to the tanks) so the added expense of an in-tank pump is to be avoided. I appreciate all the suggestions.
prichard
Veteran Member
The one I posted doesn't care where the pump is. Just drop the float in the sistern or riser
RNeumann
Elite Member
Yep the float switch is the way to go. They will live an easy life in a cistern. A lot are used for sewer ejector pumps. Their is nothing magic about them- you should have no difficulties making it work for your needs.
Valveman
Platinum Member
The Cycle Sensor does the same thing as a Pumptec, except that it will work with any pump (jet pump) as it doesn't have to be installed in a submersible pump control box like the pumptec. The Cycle Sensor is also a lot more sensitive and adjustable than a pumptec. Plus there is no float switch needing to be installed inside the cistern. The Cycle Sensor simply looks at amps and knows when the pump has run dry.
I may have to go with the float switch Prichard recommended (that's what I have in my cistern) but my friend draws on his tanks one at a time (one valve closed) so that would require 2 floats switches (unless he changes his mind). I was hoping to get ideas to utilize the narrow riser pipe, e.g. put an opaque float inside the riser pipe that interrupts a light beam when the water falls to a predetermined level. Maybe that's too complicated.
It sounds like you'd want two float switches, and some way to connect them to the valve position so that only the switch in the tank that the valve is drawing from will switch the pump.
I am starting to see what you are doing with the riser, you are trying to sense height from the pump side of the valves, it eliminates a lot of electric logic. Another advantage of doing that is if both valves are off, then there is no volume in the riser and the pump won't run.
Simplest "empty" float switch I have seen is a tube with a rising float (hollow tube a little smaller) that triggers a microswitch (can be any kind of switch, including optical). If the tank is empty, the float is on (near) the bottom and the switch closes and lights a signal (you could have it either open power to the pump directly, or trigger a relay). As soon as the float is high enough to turn off the signal (let the pump run, etc) it hits a stop. Water can keep rising as much as it wants after that, you don't care--you don't need it to tell you how much water is there, just "more than enough". Example is from a simple consumer grade humidifier.
Other nice thing about this system is the float is tall enough that the switch itself is well away from the water. No reason that couldn't be a rod that sticks up attached to a float, rather than a tall float. Total travel is about 1/2", if that.
I am starting to see what you are doing with the riser, you are trying to sense height from the pump side of the valves, it eliminates a lot of electric logic. Another advantage of doing that is if both valves are off, then there is no volume in the riser and the pump won't run.
Simplest "empty" float switch I have seen is a tube with a rising float (hollow tube a little smaller) that triggers a microswitch (can be any kind of switch, including optical). If the tank is empty, the float is on (near) the bottom and the switch closes and lights a signal (you could have it either open power to the pump directly, or trigger a relay). As soon as the float is high enough to turn off the signal (let the pump run, etc) it hits a stop. Water can keep rising as much as it wants after that, you don't care--you don't need it to tell you how much water is there, just "more than enough". Example is from a simple consumer grade humidifier.
Other nice thing about this system is the float is tall enough that the switch itself is well away from the water. No reason that couldn't be a rod that sticks up attached to a float, rather than a tall float. Total travel is about 1/2", if that.
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prichard
Veteran Member
Yes you're over complicating it. What size is the riser? How deep?
GLyford, I have seen the tubes with a rising float but I don't have the headspace to insert them, and the ones I have found what I have seen are too short. The cisterns (and riser) are at least 3' tall and maybe a foot of headspace above them.
Here's another idea: How about a float flexible enough to bend into that space, but still stiff enough to work? I'm thinking a pool noodle if your riser is big enough.
If your riser is smaller than that, how a bout a capped or plugged section of garden hose?
If your riser is smaller than that, how a bout a capped or plugged section of garden hose?
Hmmm... can the electrical connection be submerged?
