RODI problems
 

So I have a BRS 75gpd 5 stage plus RODI system. I've had it for about 3 years and up until about 6 months ago, it worked really well. During those years I have kept the unit maintained and clean. Regularly changing the prefilter and carbon blocks as needed. My TDS through this has stayed around 8 out of the RO and 0 after the DI.
6 Months ago the unit production just dropped off. I replaced the prefilter and then the two carbon filters thinking maybe something was plugged. That didn't fix it. I got a new flow restrictor as I know they can fail, but nope. I removed my auto shut off valve and the check valve in case they had failed...nope. Yesterday I got a new RO membrane and put it in place....no change. I removed my auto flush kit yesterday in case something there was causing issues...nope, no change.

I'm at a loss. I've replaced pretty much everything. When I changed the membrane, I cleaned the housing well. What else could I be missing. My pressure isn't what it should be...but it's just shy of 50psi...which is what it was all through those years of use. Right now, it takes about 10 hours to fill a 5 gallon jug...so I can't waste the water even trying anymore.

I had a similar problem and determined it was a batch of mislabeled 5 micron filters that ended being 1 microns. I just took one filter out at a time until my outlet pressure jumped back up. If you end up with all your filters out and still no flow I would start bypassing components. You may have introduced a bit of plastic from one of the wrappers that is stuck in a line.
Dan

Hmm...good suggestions. I have taken out the prefilter and tried already...no improvement. I also took out the first carbon block...but the prefilter was back in while I tried that. No improvement either. Never thought about plastic in a line as I did try to check to see if there was a build up anywhere, but nothing.
My water to start with is about 125-135 TDS

Yeah, it may be two or more stages at the same time :) if you end up with no filters and still no flow you can at least rule them out. This is what I expected to happen, but found it was one of my almost-new 5 microns plugged in just a day of use (incoming TDS only ~12ppm). I spent a lot of time doing other troubleshooting with the supplier as well. Good luck, I'm curious to hear what you find out,
Dan

This is a good idea, try with no filters inside and check the pressure, then add one and test (repeat), working in one direction to try and isolate the area where the blockage is occurring.

Since you have a pressure gauge you can use that to test at different points in your system.

1. From the tap / before your ro/di
2. Then after your prefilter,carbon block, ro

You should be able to tell where you have a huge dropoff.

Could be something clogging the tube and not the filters at all. Just a thought.

All good suggestions. Knew I came to the right place. :)

are you using a piercing valve for the feed line? the clog easily and the post can break off inside,the water pressure may be the same but the flow could be very low.

Haha...good to see people are still trying to help. In the end I took piece by piece off my system until I got more flow. It turned out the new carbon cartridge that I put in a short while before wouldn't let any water through. Getting water now :-)

Hey Mark, reading thru this thread I notice a couple of things that raised questions for me. You mention your source TDS is 125-135 and your RO output with that is typically 8. Any idea what water source you're on? Kal Lake or Duteau Creek?

Generally I'm on the Kal Lake source which gives me TDS readings of 210 or a bit higher. This can be corroborated by the RDNO water reports which list TDS as 234 from the Kal Lake intake. Earlier this year they temporarily switched South Vernon to the Duteau source due to turbidity from Kal Lake (used to be Duteau suffered more from this). The new Duteau treatment facility is evidently worth the money since that was giving me 35 TDS source! I actually started a thread on here to advise Vernon reef keepers so they could run their systems while on the low TDS source. I certainly took advantage & filled up all my RODI containers during that spell.

Nevertheless, with my 75 gpd membrane system on the Kal Lake 210 TDS source, I can get the TDS after RO down to 1 within about 5 to 10 minutes of running it. During the winter with colder input water I actually get a 0 TDS reading. Makes me think you should be getting better than 8 TDS from a 135 TDS source with your membrane. Could be that my TDS meters are out of whack, but I've only recently had to change my DI resin after over 3 years of use (2390 gals produced), so that should be a good indication that my RO output has very low TDS. Food for thought?

With regard to pressure issues, I've adjusted the PRV in my house plumbing to provide at least 80 psi downstream. I also have two pressure gauges to monitor my RODI system. One at the input shows house pressure, one after the pre filters, before the membrane. This allows me to monitor the difference & is a great indicator that one or more of the pre filters needs service.