Another RO/DI setup question(s)

[Raptor72]

@griss, this one is for you. I appreciate the advice you’ve put out there before and now I’m in need of it.
I’ve had my RO/DI system up and running for years and after reading some posts about the subject I’m wondering if I have mine set up to be the most productive. Please bear with my description as I try to describe the setup.

1- Cold water source from water heater
2- Boost pump
3- Sediment
4- 5 Mi. carbon
5- 1 Mi. carbon
6- Pressure gauge
7- Auto shutoff or splitter (it’s been a while since I installed)
8- 3 way valve ( to RO and RODI tanks) RODI valve to double DI resin to container (pump pressure switch after DI resins

Here’s where it gets a bit confusing to describe

9- Splitter to membrane set
10- Membrane to a y, manual flush on one, auto flush on other, back to y and single one again (see pic)
11- Discharge

I hope that’s clear as mud. I’d also like to color code the lines for their intended use (black, red, yellow).

 

[griss]

One thing that jumped out to me right away is the booster pump BEFORE the micron and carbon filters. IMO, you want the booster AFTER those to keep debris from getting into the booster pump.

If I have time tonight, I'll look at my system, take pics and try to respond tonight or tomorrow with more detail. I have a bit of a busy day today.

That said, don't make any changes until I can really review your post in more detail.

 

[griss]

BTW, your system looks more organized that mine Mine was pieced together over a the last 40+ years so, it's a little messy.

 

[Raptor72]

Hahaha, thanks. No rush. It’s been working fine for as long as I can tell. Here recently, I was going through DI resin very quickly and realized that it was time to change my membranes. They were pretty gross and stuck in there when I went to pull them out. It makes my water pretty quickly now.

With that, what kind of replacement frequency would you suggest for membranes, carbon and sediment filters? DI is the easiest with the color changing feature.

 

[griss]

Hahaha, thanks. No rush. It’s been working fine for as long as I can tell. Here recently, I was going through DI resin very quickly and realized that it was time to change my membranes. They were pretty gross and stuck in there when I went to pull them out. It makes my water pretty quickly now.

Thanks, I'm a very visual person, so trying to describe how mine is setup is a little difficult without pictures. Plus, as you discovered in you original post, even with pictures, it can be difficult to explain. If I get some free time this afternoon (have a couple meeting scheduled) I'll see if I can diagram how my system is setup.

Another concern that could cause the DI to deplete quickly is TDS Creep. When a RODI system sits idle, TDS will "creep" out of the membrane into the membrane housing. Then, when you turn the system back on, that water with high TDS goes into the DI cartridges and will deplete them faster. Many people use a TDS Creep Bypass to flush the TDS out of the membrane housing...this if different than your standard flush valve. It allows your source water to flow through the micron, carbon and RO and to the drain flushing out that TDS laden water.

So, when I need to make water, I open up up my (homemade) TDS Creep Bypass and watch the TDS meter coming out of the membrane housing until it drops below 10, then close the TDS Bypass and start making water.

With that, what kind of replacement frequency would you suggest for membranes, carbon and sediment filters? DI is the easiest with the color changing feature.

As far as sediment and carbon, it really depends on your source water. I find replacing the sediment and carbon every 6 months or so is sufficient.

RO membranes (as I'm sure you're aware) are rated by Gallons Per Day ("GPD") and are usually good for 3-5 years. So, in theory, if you have a 50 GPD unit and are making 50 gallons daily, the membrane should last between 3-5 years. If you're making less than 50 gallons daily, the membrane should last longer...again, depending on source water and maintenance/replacement of the micron/carbon filters.

I also recommend keeping an eye on the TDS of the product water coming out of the membrane. If it's normally 7 TDS out of the membrane and you suddenly notice that number increasing, it's time to consider replacing the membrane.

Another thing that could lead to your membrane not lasting as long is if your water company uses Chloramines in their treatment of the water. Chloramines are NOT a friend to RO membranes. You should be able to contract your water company (assuming you are not on well water) to see if they treat with Chloramines. If the do, you'll need a Chloramine removal cartridge to extend the life of your membrane. Since our water company does use Chloramines, I'll show you how I have that setup when I'm able to take pics tonight (hopefully).

 

[griss]

Okay, I’m going to have to diagram my setup out tomorrow. It’s going to to be more difficult than I thought

As I mentioned, my system has been pieced together since the early 90’s a piece here and a piece there. It’s not pretty but, it works great. Here’s what it looks like.

Once I get my fish room built, I’m going to completely redo it to make it cleaner and more streamlined.

 

[Raptor72]

It looks like it works. No rush.


Also looking at incorporating this auto flush kit when I redo the configuration, (if optimal).

 

[griss]

It looks like it works. No rush.


Also looking at incorporating this auto flush kit when I redo the configuration, (if optimal).

View attachment 32404801

Never used one of those, so I’m not sure I’ll be able to help get that installed.

I have to go to one of our branches this morning before I head to the office. I’m a project manager and we’re remodeling the branch. So, it might be a bit later when I can respond again.

 

[griss]

I hope this helps, it was a little more difficult to diagram out than I thought lol. But, as I mentioned in another thread, I'm a linear thinker so this also helped me figure out how I'm going to clean up my messy system when the fish room is completed.

So, here's how my system flows:
1. Source Water
2. Micro Filter
3. Booster Pump
4. Pressure Gauge (mine it built into the Carbon cartridge housing)
5. Carbon Cartridge
6. Chloramine Cartridge
7. Input 1 of the Shutoff Valve
8. Output 1 of the Shutoff Valve
9. RO Membrane - Product Water (I'm leaving waste water out because I think the diagram should be self explanatory)
10. First TDS Probe (I have a dual TDS monitor, one for RO only and one after the DI Cartridges)
11. Input 2 of the Shutoff Valve
12. Output 2 of the Shutoff Valve
13. Booster Solenoid
14. T-Fitting to Flush out TDS Creep
- 14a. When I want to start making water, I open this valve and let the water flush the membrane until TDS drops to a 98-99% rejection rate)
- 14b. When I close the valve in 14a, water then flows to the DI cartridges
15. Cation Resin
16. Anion Resin
17. Mixed Bed Resin
18. Second TDS probe
19. Water Storage

 

[Raptor72]

Ok, I’ll look it over more at work. From what I understand from the description, the auto flush valve I’m looking at would go in place of your #14 and do it automatically.

 

[griss]

Ok, I’ll look it over more at work. From what I understand from the description, the auto flush valve I’m looking at would go in place of your #14 and do it automatically.

Sorry for any confusion, this is a bit difficult to explain in print. Actually, this (red arrow) is where you would want to put the auto flush valve, on the waste line.

Flushing the membrane and removing TDS creep (my number 14) are two different things. My number 14 is actually a DIY TDS Creep Bypass Valve. Here's a link to a commercially available TDS Creep Bypass.

Flushing the membrane actually bypasses your flow restrictor and forces water across/through the membrane, helps to clear any debris/build up that may have be in/on the membrane. This extends the life of the membrane and increases the ability of the membrane to remove impurities. Mine (red arrow above) is a manual Flush Valve that I simply open once a month or so to clean the membrane.

My number 14 is to only to clear any TDS creep out of the membrane housing (outside the membrane on the purified water side) before making product water to keep from exhausting your DI too fast. When your system sits idle (not making water) total dissolved solids ("TDS") "creep" out of the membrane into the clean water side membrane housing. Then, if you don't remove this TDS prior to sending water to your DI cartridges, that high TDS water will go into the DI and exhaust it faster.

I have a shutoff valve (which I neglected to put in the picture above but, now indicated by the purple arrow in the graphic above) right before my first DI cartridge and another below the T-Fitting shown above. When my system has sat idle for a while, I need to remove the TDS from the clean water side of the membrane housing so I don't exhaust my DI too fast. I close the shutoff valve (purple arrow) between the T-fitting and the DI and open the shutoff valve (green arrow) to waste. This flushes the built up TDS from the clean/product water side of the membrane housing. I then watch the first TDS probe reading on my monitor and when it drops to an acceptable range, I close the valve to waste (green arrow) and open the one to the DI (purple arrow).

 

[griss]

Looking at your pictures, I believe this is where you want to put your auto flush valve.

 

[griss]

Check this out.

Install an Auto Flush Kit on your RO/DI | How To Tuesday

Properly flushing your membrane will maximize system efficiency, improve rejection rate and prolong membrane life. The thing is most of us forget to do it before and after using our system and almost none of us do it while the system is running. That’s where an auto flush comes in. All you need to

www.bulkreefsupply.com

 

[Raptor72]

Sweet, the auto flush valve is only half of what I was going to pay since I already have the booster pump installed.

Is there’s such a thing as an Automatic TDS creep valve? Asking for a friend

Trying to make this as hands off as I can.

 

[griss]

Do you know where your flow restrictor is on your system? In some older systems, you had to actually insert it inside the waste water tubing after the membrane.

 

[griss]

Hmmm, maybe you won't need to worry about TDS creep with this auto flush flow restrictor? From BRS' website.

 

[Raptor72]

Do you know where your flow restrictor is on your system? In some older systems, you had to actually insert it inside the waste water tubing after the membrane.

I want to say it used to be here instead of the auto flush valve.

 

[griss]

I want to say it used to be here instead of the auto flush valve.

View attachment 32404846

Oh, that’s the auto flush valve? Didn’t realize that.