Simple RO/DI gadget

[OldReefer]

I was trying too noodle this through myself, and then I remembered this forum was full of helpful electrical engineers that void tell me how to do this right....

 

I am helping a friend with his first tank build. I am trying to help him setup a way to fill his RO/DI container up without overflowing.

 

I have a 12v solenoid valve, a float switch that clips to the side of the container which is normally closed until it fills up, and a 12v power supply.

 

I would like to set this up so that he can push a momentarily on button and have the RO/DI run until the container is full, and then shuts off. It would stay off until the water level goes down and the button is pushed again.

 

My thought was to use a simple latching relay, but I wasn't sure where to find one. I am also open to suggestions as to how to best wire it.

 

[Coral Hind]

I agree you will want a latching relay so the holding circuit will keep the coil energized and the float switch will be in the holding circuit to open it. I'll look to see if I can find something with minimal DIY.

[hypertech]

Sounds like a complicated to solution to not a big problem. A mechanical float and ASOV will let it run adn shut it off when its full. Then turn it off at your leisure until you are ready to fill it again.

[Guest thefishman65]

How about a mechanical (spring wound) timer (not as fancy but easy). You can find 6 and 12 hour ones. Rather than push a button you turn a knob. Also you have double redundancy no power no flow flow and not wasted energy.

[scott711]

do you have a controller? Would be easy to write a program to do that.

[OldReefer]

I have an elaborate setup with a controller at home. I am doing this for a guy starting a first tank on a budget. I use a float valve and and ASOV on my own system as a backup, but if that was the only shutoff, it would cycle constantly and wear out the membrane early. I'd like to let the container drain down a bit so that the RO/DI runs an hour or two each time. Of course you can switch it off manually.

 

I did something similar to that on one system I had, I just wired the 12v power supply, float switch and solenoid valve in one simple circuit. Every Saturday morning I would plug in the power supply and let my 50 gallon container fill up. When it was full the float switch would shut it off. Later that afternoon I would unplug it so that it wouldn't cycle as it was being used.

 

I am trying to be a little more sophisticated this time, but stopping short of an Apex and multiple float switches like I run on my own tank.

[DaveS]

I use a float valve on the output with the ASOV. I think have a simple valve on the input to the RO/DI. Unit produces water overnight until shut off by float and ASOV. Then in the morning I just turn the input valve to off. Yes, things cycle on/off before I get around to turng off the water but it's not much. My reservoir is large enough that I only need to make water once every 2-3 weeks.

 

When I added a booster pump, this made things a little more complicated but doesn't sound like an issue here.

[ctenophore]

Bill, I may be able to help you with this. Dan and I have been cooking up something that solves this exact problem. If you can hang tight for a few weeks, I may be able to get you a close-to-production prototype to try out.

[OldReefer]

Justin,

 

I will never pass up an opportunity to beta test for Avast. I thought that pirate ship had sailed when Dan moved out of Del Ray. I will do something simple while I wait to test something cool from you guys.