RO/DI setups

daplatapus

New member
First off, let me describe my RO/DI system then I'll pose a couple questions. Bear with me, I know this post is going to be lengthy.

I have a "The Filter Guys" OCEAN REEF MISER SIX STAGE RO/DI 100 GPD RO/DI system with an added booster pump.
Water comes into my booster pump, through the 3 pre-filters, then 2 RO membranes, then through a pressure switch which controls the booster pump, then into my 2 DI cartridges, and finally through the float valve in my Brute tub.

The Problem: With this system, my wastewater never stops running. Which is normally not that big a deal. I store roughly 25 or so gallons of water, so I only make water a couple times a month. That's when I go down, turn the water on to the system, turn the booster pump on, and wait for it all to fill up. Once the Brute can is full, the float valve closes, creates back pressure which turns off the pump. BUT... the waste water keeps flowing. So I have to remember to go down and shut everything off. Something which I have forgotten a few times until the next day. So I'm looking at finally fixing this system.

I have been under the assumption that it really isn't all that good for the pump to come on for a few minutes a few times a day. Although I'm beginning to wonder if that's not such a big deal. I mean, systems used solely for drinking water under sinks do that all the time. What I must admit, is I don't like the sound of that booster pump coming on in the middle of the night as it tops up my Brute.

It has been pointed out to me what I am missing in my system is an Automatic Shut Off Valve and a check valve in the permeate tube between the membrane and the shutoff valve.

After talking to a guy at Aquasafe is Sydney yesterday, I'm not sure if this will work either, unless I have a pressure storage tank. My understanding of this whole system being truly automatic is the check valve and ASV (auto shut off valve) rely on the back pressure created by a pressure tank. While the float valve in my Brute will create some pressure, as soon as a few millimetres of water is used by my ATO, the system would come on. While if I had a pressure tank, my understanding is I could use up several gallons of water before the system replenished itself. Depending, of course, on the size of the pressure tank.

So, I guess here's my questions:

1) Does any of this make sense or have I got fundamental flaws in my understanding of how these systems work?

2) If I DO have this all straight, why are we using 30 gallon Brute cans to store FW for ATO? My system, for example, probably uses up 3-5 gallons a day in evaporation. If I had even a 4 gallon pressure tank reservoir or even 2 in tandem (for a total of 8 gallons of FW), that would more than likely suffice for my day to day top off.

3) If all the above is correct so far, is it possible to allow a Tunze osmolator to operate a solenoid valve instead of a water pump that would open, allowing water to drain from the pressure tank into the sump when the infrared eye deems necessary?
 
Had the same problem - bad auto shut off valve.
As for a reservoir - really not what we want - frequent start & stops will not do the membrane anything good. Scale will build up & reduce its lifespan along with the water quality. The longer you run the unit the better it is - up to a point of course.
 
Mine never came with the ASV or check valve. So the system works as given, I just don't like how that is, lol.
How have you got your system set up then? What gives you that back pressure to allow the ASV to work properly?
 
Check out the Valves section on the Spectrapure website.
1st one on the page with connections for 4 hoses, $12.99 if I remember right.
This is what I needed.
I'm sure The Filter Guys can solve this also.
I say hi to one of the fellows @ every MACNA.
 
no need for a tank, the float valve will close creating back pressure.
You need a check vlave, you alreaky have the ASO.
 
Same here, I use float valves in both my top-off reservoir & salt mixing container - both hold about 30G.

Those are only so I don't have to baby sit them when I'm filling em though. I shut the feed water supply to the RO/DI off once I check and see the reservoir is full.
 
Hey guys - a couple of comments on the original post:
1. We'd recommend you move the pump location. It is better to have the pump AFTER the prefilters. Here is a generic configuration when controlling the pump with a high pressure switch:

Buckeye-Hydro-HP-Booster-Config_zps372b9df8.png


2. Especially because you already have 24vac power at your system, you'd be better off with a shut off solenoid, rather than a typical auto shut off valve. Don't use any old solenoid here, as it will be powered for long periods of time, and low end solenoids don't do well in this situation.

You absolutely don't want the waste water continually running. Other than the obvious expense/waste, remember that all that waste water is using up the finite capacity of your sediment filter and carbon block.

Russ
 
Last edited:
I have been under the assumption that it really isn't all that good for the pump to come on for a few minutes a few times a day.

Short-cycling should be avoided for a number of reasons. There are various ways to work around this. Please call in if you'd like to discuss/solve this.

Russ
 
Thanks for all the comments guys!
I went out and picked up a check valve and ASOV and went down to put them in. And guess what I found? Hiding in behind my 2 RO membranes tucked nicely out of sight was a ASOV, lol.
BUT... there was no check valve.
SO I cut the check valve in and ran the system. IT WORKS! When the float valve in my Brute shuts off and the pressure climbs up, the waste water shuts off now. YAA!

But, if I truly want it to be automatic, unless I put timer and solenoid or something on it, it is going to cycle rather quickly. Every time my Tunze osmolator adds water to my sump, the RO/DI is going to kick in.

Russ: I'm in Canada, so I'd rather try and avoid an international call :) Can you explain why the booster pump should be after the prefilters? I've not heard that suggestion before. And I like the idea of the solenoid to turn the water on and off. Using my Apex that shouldn't be a big issue. But I'd imagine you'd want to make sure the water gets turned on before the pressure pump does. I doubt it's good for the pump to run dry.
 
If you get the right one, the shut off solenoid will plug into the same wiring harness as your pump. It is A REPLACEMENT FOR the hydraulic ASOV you're using now.

When the pressure switch senses that the float valve is closed, it turns off the electrical circuit and the pump turns off and the solenoid on the feedwater line closes - stopping all flow before it reaches the RO membrane.

Aquatec booster pumps can run dry w/o damage.

With your current set up you may find that the pressure switch, and the ASOV "fight" with each other causing the pump to repeatedly kick on and off.

If you want the system to not short cycle, consider something like our Hi-Lo Controller. It will keep the RODI reservoir level between the High Float Switch and the Low Float Switch. because of the vertical distance between the two switches the pump etc won't short cycle. You'd plug the pump transformer into the Hi-Lo Controller outlet.

Russ
 
Russ: I'm in Canada, so I'd rather try and avoid an international call Can you explain why the booster pump should be after the prefilters? I've not heard that suggestion before. And I like the idea of the solenoid to turn the water on and off.
Sure. The weakest component in your entire system, in terms of ability to withstand elevated pressure, even if you use high quality NSF housings like Buckeye, is your clear housings. By placing the pump AFTER all prefilter housings, you avoid exposing them to elevated pressure. All that sees the elevated pump pressure are fittings, tubing, and the RO membrane housing - all of which can typically handle higher pressure.

Russ
 
Thanks Russ!.
Have you got a part number I can look at for that solenoid and the Hi-Low controller? Definitely sounds interesting.
Have you ever heard of issues with the pump starving for water if someone is neglecting changing the perfilters and the pump has to work hard to GET water?
 
Shut Off Solenoid Valve, 1/4": http://www.buckeyehydro.com/shut-off-solenoid-valve-1-4/

Wiring Harness Splitter: http://www.buckeyehydro.com/wiring-harness-pigtail/

Hi-Lo Controller: http://www.buckeyehydro.com/hi-lo-tank-level-controller/

YES - we just had a service call at a pet store where their system wasn't working right - noisy pump, too much waste water, slow production, low pressure. Problem ended up being clogged prefiters starving the pump for water. But again - these types of pumps can run completely dry w/o damage. This is an unusual problem and is typically indicative of someone not paying attention to routine maintenance.

Russ
 
Back
Top