Garage Sink/Emergency Water Tank Float Switch problem

djsfantasi

Joined Apr 11, 2010
9,156
Thanks djsfantasi for your quick response. This is awesome. I did however go with the relay approach for my particular application, but I really appreciated your input getting me pointed in the right direction with adding hysteresis to my system.

Greg S.
You’re welcome. No worries. This is a collaborative forum, where one can get many answers!
 

Picbuster

Joined Dec 2, 2013
1,047
I have designed a sink for my garage that uses two 55-gallon emergency water drums as the water source (they are stacked on top of each other so I have 100 gallons of water reserve). I wanted the tanks to auto-fill from an ice maker water line I tapped into the back of the washing machine (which happens to be located just behind the wall). To make this work, I have installed a simple N/O (normally open) floater switch in the top tank to guage when the tank is full. I have attached it to a 12v N/C solenoid which controls the water flow to the top of the tank. In theory, when the floater switch is “open” (aka the tank is not full), it triggers the solenoid to allow water to flow into the top of the upper drum. Once the drum is full, it triggers the float switch and turns off current to the solenoid. The system works exactly as planned except I have one small glitch...

When the water tank is nearly full, the float switch sometimes opens/closes rapidly (probably due to water movement within the tank), which causes my solenoid to pulse on and off until the float switch finally settles down and remains an open circuit. I don’t like how the solenoid pulses like that, so I am looking for a simple circuit I can connect to the solenoid that will filter out the rapid on/off signal received from the float switch, until the switch remains in a constant “open” position for longer than a few seconds. Does that make sense? I can send photos/basic schematic of my system if that helps. Thanks for any guidance I could get.
nice to have a water backup however I see one problem with the N-O switch.
When open it starts filling the tank close will stop filling but what happens if the cable is broken (contact open).

The best way to overcome this problem is to use a 3 pool switch (when both open or both closed huge (mechanical) error.
An other way is to measure water level ( pressure) but here also the 3 pool switch.
Electronics I, as a real Pic buster, will advice pic + fets however; relay, diodes,resistors,caps plus a few transistors could do the job.

Picbuster
 
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