Relay help. ATO

[Snaz]

Originally Posted by mike31154

Instead of making things more complex with a relay, have you considered making it simpler instead? I have a similar ATO with an air pump pressurizing a container but use a mechanical furnace humidifier float switch to limit the fill level rather than an electrical float switch to turn a pump on and off when the level drops. I use a regular, small aquarium air pump plugged into a timer which cycles on for a few minutes every hour. This keeps the top off container sufficiently pressurized to keep up with evaporation, while the mechanical float switch keeps the level from rising above the set/desired level. Once you've got the timings dialed in to keep up with evap, it works like a charm and if the pump happens to run a little longer, no harm done, the float valve prevents any likelihood of overfilling. Less electrical around water = more warm & fuzzy safe feeling.

I'm intrigued. How big is the float switch? I have to mount it in a rear chamber that is 3.5" x 3.5",

[mike31154]

Originally Posted by Snaz

I'm intrigued. How big is the float switch? I have to mount it in a rear chamber that is 3.5" x 3.5",

Hmm, that's a bit of a problem since the valve assembly (not switch) takes up a good 9 inches mounted on the rim of my 77 gal display. Since it's designed for a whole house furnace humidifier it needs to be fairly long to have the leverage to shut off a water line under house pressure. In our application with the air pump there's not even close to that amount of water pressure on the valve. Another alternative could be to look for a shorter valve assembly such as those used to shut off a RO/DI system. Might also be able to shorten the type I have since it has three open chambers at the underside that trap air to push it against the stop Not sure if it will work on only one chamber and if that's sufficient to keep the valve closed. Here's a photo, they're available for about 10 bucks at most home reno stores.

Float valve, I made the mount assembly out of scrap acrylic and used nylon bolts to secure it to the tank



My pressurized 7 gal glass wine carboy, good for a week's worth of ATO



By the way, if you decide to go with a mechanical valve and are able to locate your top off container above your sump (assuming you have a sump) you can dispense with the air pump too and set up a gravity fed ATO.... no electrics at all... That's my plan when I get around to setting up a basement sump.

[mike31154]

Here are a couple of links to alternative float valves, I think they're shorter than the one I'm using, but might still be longer than the 3.5 inches clearance you have.

http://bwiplumbing.com/index.php/aqu...oat-valve.html

http://www.marinedepot.com/Kent_Mari...RAFV-5-vi.html