I replaced the water filter cartridge at the bottom of my fridge. At the top of my fridge is an LED that is glowing green after I reset it by pressing a button 5 times within a 10 sec period. How does the LED know when to turn red?
WAG is that the circuitry monitors the amount of time that the inlet solenoid is energized, which relates to the amount of water which has flowed.
Most likely, it’s something as simple as changing state after so many hours of usage. A timer circuit runs whenever it senses a water pressure drop and when the total count reaches some preset value, it turns the LED red.
So, is it a timer circuit, eg. 6 months, or a water volume measuring circuit?
The two are directly related. The manufacturer has determined that the water flow solenoid will flow x gallons per minute if held in an open condition. If they want you to replace the filter after y gallons of water have flowed through it, a time amount can be calculated, using the above data.
That makes excellent sense - thanks.