Lazy Mans Auto City Water Tank Fill Modification

[Midnightsun]

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.

[Viper]

That's more elaborate than the system I put on a previous boat. I just used a diverter valve installed after the fresh water pump and teed it into the line between the tank and pump to bypass the pump's check valve then simply keep an eye on the tank gauge. When it reads full, leave on for a few more minutes then return the valve to its normal position. Many ways to skin a cat but you really gave yours a lot of thought

[Midnightsun]

A manual diverter valve would work fine but then you might as well sit there and wait for the overflow using the good old hose in the filler port method. This sort of automates it without the need to stand on watch which is a pita. My boat has the filler port at the aft deck whcih basically overflows into the boat (stupid design but easy access) Biggest issue I find as we get older is we tend to forget more and more so this kinda eliminates those brain farts if you know what I mean. The filler port is behind those blue swim tubes you see hanging in the picture below.

https://photos.smugmug.com/Midnight-Sun ... 4320-L.jpg

[Viper]

Source of the post.... Biggest issue I find as we get older is we tend to forget more and more......

True dat. Look on the bright side, some things are worth forgetting......wait a minute, I guess I'd rather forget with a case of beer than getting old though

What were we just talking about?

[Midnightsun]

Was at the boat today preparing a bunch of stuff for launch in the upcoming weeks. Took a good hard look at the project and there is a large access hole on the top of the tank so installation of the float switch should be a breeze. Just need to get delivery of the parts I ordered mostly sourced from China so several weeks at best. Will post some pictures as the project progresses.

[Midnightsun]

This will take some time as parts coming mostly from USA and China. Had the float from my aquarium stuff so installed it.

Had an easy access hole on top of the tank or at least it seemed so. Opened the large cap to find it was not pierced yet. A hole saw took care of that in no time.


A small 3/8" hole, a dab of 4200 and float switch is now in place.

[Viper]

Good project

[Midnightsun]

Got my countdown timer yesterday so I mounted it in a 4' X 4" nylon box and tested it out. Works exactly as I was hoping.

Just need my solenoid and fittings to complete the install.

[jcoll]

Great idea. You got me thinking - winter project Where did you source power from? What did you use for circuit protection; breaker or fuses? Did you relay any of the components or is it all straight runs from source and back?

[Midnightsun]

The 4x4 junction box will have multiple duties. 1) serve as a wire junction box (12vdc, timer, relay, float switch) 2) serve to house the timer as shown 3) serve to house a relay as the float contacts are only good for 500ma whereas the solenoid requires 700ma.

I updated the photo above to show the relay installed and a picture of the fuse holder.

Power can come from any available always powered location as max draw is 700ma and will only happen when activated for a max of around 10 minutes assuming the tank is completely empty. The led digital display is always on however the draw is probably in the single digit ma range. I happen to have a conveniently located + and - busbar that I will be tapping into along with an in-line spade fuse holder and 5A fuse. Will post pictures as things progress.