Tank moved, new journal

[danny zubot]

Right to my RO unit.

Which brings to mind a concern of mine. Since the valve on the RO unit needs to be open at all times for the system to work, its always dumping waste water down the drain. Is there any way around this? I was thinking of just closing the main valve for the RO unit a bit so that less water will be wasted.

[Delphinus]

Hmmm, Ok I was kind of worried you were going to say that. Having been down this road myself .. let me spare you some things I learned the hard way.

First of all, in answer to your question, what you want is a solenoid shutoff kit for your RO/DI unit. The float valve closes, the output line pressures up, and this pressure drives closed another valve on the input side of the RO/DI. Thus, when the output valve is off, the unit is off, no longer dumping waste water.

But !!

That's still not quite enough. The problem with this scenario is that the water will get replaced at the rate of evaporation. Which could mean that you end up having the unit on for like 10 seconds every 5 minutes. This is very hard on the RO membrane, I ended up going through 3 membranes in a year until I figured out what I was doing was killing my membranes (the RO would output TDS at 80-100 .. the membranes were shot).

So.. you need a sort of buffer in between the sump and the RO/DI. What I do is I have a bucket I use as a RO/DI reservoir. In my case it's like a 50g food grade barrell. I fill it up manually and let it fill overnight (it still has the shutoff kit so no worries about overflows), and then turn off the RO/DI manually. This lasts me about 2 weeks between fills. (It's still not a perfect arrangement - more on that later). Then, basically the float valve on the sump is attached to the reservoir. So the water can enter into the sump at whatever rate the evaporation is, and I don't have to worry about destroying my membrane.

Now .. (here's the "later" part I promised..) It turns out that it's also not great to have your RO/DI sit idle for 2 weeks at a time because you still get TDS creep. Right now I find myself having to flush the membrane every time I run the unit, which shouldn't be necessary.

What would be perfectly ideal is have a sprinkler timer on the input and have the RO/DI turn on for an hour each night. Thus it still has the benefit of a single run (ie., when it's on it's on, and the shutoff kit is then at that point a failsafe in case the bucket fills to the top), AND it has the benefit of not allowing the TDS to accumulate.

There is a clever design of a reservoir using a check valve that basically allows you to have it self-fill if (and only if) the reservoir empties completely. I don't have the URL handy but it was talked about on Canreef so there are some threads on it somewhere. I figure the hose/sprinkler timer thing would work fine too (I just have been too lazy to look for one at HD. I probably will when I get my basement further along.)

This is the shutoff valve kit: http://www.jlaquatics.com/phpstore/s..._ID=ro-kpfshut

This is the flush kit:
http://www.jlaquatics.com/phpstore/s..._ID=ro-kpflush

(Although they are "Kent" brand it doesn't really matter what brand you use - they just fit on 1/4" tubing basically, so they will work on other brands of RO/DI units.)

[Delphinus]

Ah, here's the thread I'm thinking about. I see I whined about, er, mentioned wrecking my RO membranes in that thread too.

http://canreef.com/vbulletin/showthread.php?t=29834&

[danny zubot]

Hey Tony, thanks for all of the information. I like Kent's auto shut off valve the most, but I'm concerned that I won't be able to fill my drinking water jugs without a great deal of hastle. Since it works on pressure it should release when I switch over to "jug" mode should it? In a minute I'll post pics of what I have so you can see what i'm talking about.

[Delphinus]

I think you should be able to make it work. I do something sorta similar. I've never actually used my RO for drinking, but I do T off the RO/DI before the DI stage to go into another reservoir which I use for watering my orchids. Some of the fussier orchids need to be watered with RO water but you don't want to use RO/DI for this, just RO. Anyhow so I "T" off the line going from the RO membrane to the DI canister into a rubbermaid type thing with a float valve. So when that thing is not full, the "priority" is to refill it (although some water makes it past the DI so the RO/DI output isn't completely "off" but it is "slowed"). When it's full, it stops filling and all the water goes to the DI.

Basically with the autoshutoff kit, you can have as many outputs as you want, as long as they go to some kind of shutoff (float valve, typically), when they are all closed, the output line will pressurize and close the input valve. If any one of them drops, the output line will depressurize, and the input valve opens and away you go.

Basically it's full automation without any electrical components, it's actually kind of neat.

[Der_Iron_Chef]

Hey, just reading this and it has me interested for when I set up my own RO/DI top-off system. Danny, is this relatively close to your set-up (ie. output from RO t'd off--one for drinking water, one to the DI?)

[danny zubot]

Here's the set up right now. I have the stock RO valve, a "T" to the top off side and the Jug filler, both with their own valves. The Jug side remains closed unless I'm filling, and I added a valve to the top off side to close it off when filling jugs. This is to prevent a back pressure siphone out of the sump. (Wouldn't that taste nasty?)

So the way I see it, regarless of where to water is going, if the system is depressurized the selenoid should open up right? I'm not worried about the auto shut off working when filling jugs because I only do that when I'm around to keep my eye on it. Let me know what you think.

Oh, and I've thrown in a few extra pics of the system just for fun.





How NOT to wire your system.

[danny zubot]

Danny, is this relatively close to your set-up (ie. output from RO t'd off--one for drinking water, one to the DI?)

I've run the line from the filter up to the ceiling, across the room and down to the sump. It's about 25 feet of line.

[Delphinus]

Danny, where did you get the picture of my electrical setup???

Anyhoo, yeah, you'd be fine with what you're describing. Basically as long as you have a valve (in this case probably just a ball valve like the ones pictured on melev's setup that Drew showed there), all you have to do is close the valve when you're done, the line pressures up and the input valve closes. Open it up and the unit turns on, close it up and the unit turns off.

Drew, FWIW, what you have pictured there is exactly how I have mine setup, except that instead of ball valves at the end of each line, I have float valves on reservoirs (since I'm somewhat bad at forgetting that I have water on and tend to create large pools of spilled water - see signature ). I just use the $10 humidifier float valves from Home Depot/Rona/etc.

[danny zubot]

Well, I got the auto shut off valve last night. After several hours of scratching my head and the odd curse word I got it installed and working. The instructions are for the Kent filters and utilize parts existing on them. Long story short, it works, so no more wated water.