This project has been in my head for several years but never got around to implementing it. Basically I would like to fill my potable water tank with the hose that is already connected to the city water supply when at dock as opposed to a hose into the filler hole.

Using a solenoid, a float switch, a momentary push button activation switch and a timer it is pretty much failsafe. Install a small float switch like this in the top of the tank. https://www.ebay.com/itm/Hot-Sale-White ... %7Ciid%3A1 This will automatically shut the solenoid valve https://www.ebay.com/itm/1-2-NPT-12V-DC ... 2749.l2649 off when the tank gets almost full. Add a timer into the same circuit as the float switch/solenoid and set to appropriate time interval (15 minutes?) https://www.ebay.com/itm/DC12V-24V-LED- ... %7Ciid%3A1 this cuts off the supply if the float switch fails. Install a momentary push button switch which activates the solenoid. https://www.ebay.com/itm/16mm-Anti-Vand ... SwZVlXqas3


How it works. When connected to city water and you want to fill your tank. Push the momentary button you installed which activates the timer which is connected to turn on the solenoid until the float switch cuts the circuit off and shuts off the water supply filling the tank. If the float fails for whatever reason (highly unlikely as I have these same floats in several aquariums that have been running for many years without failure) the timer will run out and shut off the solenoid after the predetermined max run time you set it to.

Possible vent issue which could cause tank expansion. Add a vent or simply open the fill port for air expansion when in use. Technically the vent is 5/8" and the water feed line is only 1/2" so there should not be a problem however we all know vents will plug with time so an additional vent or tee off from the existing vent would not be a bad idea if not using the opening fill port for air displacement.

Oh boy, another project but hey, this is part of boating fun for me. Love this stuff.