DIY: Auto Top-Off Controller

I'm going to try and make my own auto top off controller. My friend did a diagram for me a few months back and I posted a picture of it somewhere.

I'm not really sure how complicated I should make this. One part of me wants to make the whole thing electronic and just trust it. The other part of me wants to use a manual float valve - but I don't know why I would bother. If ya got one electronic float valve in there, ya got no reason not to use 2 or 3 of them instead of a manual one.

I am going to use a small bucket or maybe a 5g tank for an RO reservoir. Not sure how to keep it full. I'd like to mount an electronic float switch in the reservoir and have that control the RO pump. That would need a transformer and a relay of some kind to turn the pump on and off. I want a water solenoid too, so I don't have water pressure on my RO pump 24/7. Can get a water solenoid in 12v or 24V.

It seams like I just need a metal box to mount some electronic stuff. But I have no idea how to wire it all. I know exactly what I want to do, but I don't know what electronic components to use and how to wire them.

Is there an electrician in the house?

OK so I got this straight, you are wanting to turn on a pump with a float valve that will fill up the sump for your tank.

Get yourself an electronic float valve that makes when the water level lowers. Get a relay rated for switching 120 volts and a coil rating of what ever control voltage you are using. The float valve will energize the coil on the relay and turn the pump on. Once the water in the sump fills back up, the float valve will shut off de-energizing the relay which stops the pump.

Then have a second float valve in your resevior bucket and once the water level in that gets too low, it will energize a second relay which will open the solenoid valve that feeds your RO unit. If that unit has a booster pump, you will need to either have a third relay or the second relay needs to be a double pole relay cappable of switching both 120vAC for the pump and 12vDC for the solenoid at the same time. Or get a 120vAC solenoid and just have them both running off the same relay.

Here's kind of a basic picture of what I want to do. I can think of several ways to build in redundant safety devices to shut the whole thing down in the event of any flooding. But it makes it pretty complicated.

The picture I loaded in my first post has all the safety devices built in. High water level in the tank - high and low water level in the sump - high or low water level in the RO reservoir tank. I think it would work.

The picture in this post is a basic version of how I'd like to do it. Basically, when the sump gets low, the electronic float would trip a relay and that would energize the power to the small powerhead in the RO reservoir. The powerhead would turn on and pump RO water into the sump. When the sump is full, the float goes up and shuts off the relay. Power to the pump stops.

The RO reservoir works the same way. When the reservoir gets low, the float trips the relay. The relay opens the water solenoid from the main line and lets water into the first 3 stages of the RO unit. Then it goes to the RO pump, through the membrane and the DI cartridges and finally into the reservoir. When the float rises up, it closes the relay and power to the solenoid stops - solenoid shuts off - power to pump is also shut off at same time - pump shuts off.

To me, it would make more sense to just move to top-off pump closer to the top, that way if something goes wrong in the sump's return to the tank, it will not over flow. The pump would be high enough in the tank so that the water would drop below the pump....

I am pretty sure my sump can handle the entire 5g of RO top-off water if anything happens.

I found waterproof electric switches that are bulk head type. My brain is going crazy now. I think I can do exactly what I wanted to do all along.

Nice. Good luck RC!!!!

Give us some pics

good luck! looking foreward to the results!

The FTL-227 float is a horizontal mount. It's a 12mm thread size, so I'll go to RichonTools and get a hole saw bit for probably $10 or less. These floats will work on any voltage up to 50V.

http://www.chicagosensor.com/Horizon..._Switches.html

My current transformer that powers my RO pump is 24V and 1.2 amp output. The pump only takes .2 amp, so that transformer can power several float switches. I'll run this transformer all the time to power the float switches. They take like 10 watts to power. Each float switch needs to turn a relay on and off to manage the 110V power for the powerhead.

This would be a piece of cake if I could find a 24V powerhead.

EDIT:
Found a few 12v powerheads

Why not get a second 24v RO pump to use as your top off pump?

They aren't submersible - I don't think they are. ??

Do you know of a source for a submersible RO pump?

Didn't want to plumb it outside the reservoir tank.