Sensing water level in cistern

   / Sensing water level in cistern #1  

MillWeld

Gold Member
Joined
Feb 17, 2011
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410
Location
Durham NC
Tractor
Ford 641
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.
 

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   / Sensing water level in cistern #2  
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.
 
   / Sensing water level in cistern #3  
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.

Yeah, that seems cheap and easy, my two favorite things!
 
   / Sensing water level in cistern #5  
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.

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

pumptech.JPG
 
   / Sensing water level in cistern #6  
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.
 
   / Sensing water level in cistern #7  
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.
 
   / Sensing water level in cistern #8  
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)
 
   / Sensing water level in cistern
  • Thread Starter
#10  
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.
 
 
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