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RO/Top Off Automation Discussion

Posted: Sun Dec 11, 2016 7:31 am
by robmwpropane
So I'd like to get some feedback and brainstorm about this. My plan is to at some point buy the 12v power expansion and use it to control some 12v RO relays to automate the process.

Right now, I manually do all this when my brute trashcan (gravity fed w/float valve into sump) RO container gets low (or my return pump starts blowing air into the tank because I forgot). I have 3 valves. Feed, dump before DI resin, and 2 "T's" to loop around the restrictor to flush the membrane some. When I start, I open all 3 valves and let it run until TDS are below 15 or so. I then close the valve to divert water into DI, and close the line to active the restrictor.TDS meter is on the output from membrane, and then on the output from DI.

Also I have an RO booster pump, as I'm on a well. It has a cutoff at 40psi, but has NEVER worked the way I wanted. I belive the float valve in the resovior allows the 40psi to drop, and the pump comes back on. I have the pump on a timer that I guesstimate when to shut the pump off. My system works, but way too much room for human error...ask me how I know...too many floods to count.

I found these on Amazon for $7!
https://www.amazon.com/DIGITEN-Solenoid ... B016MP1HX0

Where I'm coming up short is failsafe's in place, or what could go wrong? I'm thinking to have timers (in the code) to set off alarms if anything takes longer than it should to fill the resovior, or maybe just automatically turns the system off (better to have 30gallons on the floor than 100) How reliable are solenoids, how periodically do they need cleaning/servicing?

Right now, I'm thinking I need 3 solenoid valves, and get everything wired up. I just wanted to hear other people's experiences, mistakes, etc. before heading down this road. Pictures of your setup would be great as well, and if anyone knows how to service the valves like I posted above that would be great. (I searched Google, but nothing on those, just a couple videos on the ones that look like a regulator).