RO membrane failure

[BSamuelson]

Just wondering if anyone else has had problems with RO membranes failing in 2-3 months.

I have tried 2 different brands of membranes and carbon blocks. The system started out getting the correct decrease in TDS (about 375 down to 5) but after a few months the TDS starts rising and flow increases. This would indicate that there are holes forming and not the filter getting clogged. Pressure is about 60psi from the town of Owego. I use it for top off, water changes and drinking water. Its hard to believe I am using 10,000+ gallons in 3 months and depleting the carbon block but that is the only thing I can think of.

Has anyone had a similar problem or an idea of what I am doing wrong?

Thanks

 

[justthewife]

I think something like this happened to ours when we first got one. I will ask my husband.

 

[Gumpy]

I think something like this happened to ours when we first got one. I will ask my husband.

I did have some problems with the original unit I had, but doesn't sound quite like the problem you are having. On my unit, the ratio of product to waste water was never right even after getting a replacement membrane. My DI Resin was being used up very quickly. After switching to a BRS 6 stage unit and getting a pressure valve to reduce my water pressure to 50 psi things are going great.

The only thing I can think of would be to check the chlorine level in your product or waste water. If your carbon blocks are getting depleted, I believe that the chlorine can damage your membrane.

 

[BSamuelson]

I have a new membrane and carbon block showing up this week and will try to get a chlorine reading before and after I change things. I actually went to a needle valve to set the ratio of product to waste so I knew what I was getting but that did not help. Maybe I will try BRS next if it fails again.

Thanks

 

[BSamuelson]

So, with my new membrane I also got a new housing with a pressure gauge built in. Looks like the pressure is going too high when things turn off and this is what is blowing my RO membranes.

Municipal supply: >100psi
After whole house pressure regulator: 70psi with any faucets running and >100psi when faucets are all off.

So either the pressure regulator is shot or the expansion tank on the house side is not pressurized anymore.

 

[Gumpy]

My pressure was way too high as well (about 100 psi). I bought a Watts P60 Water Pressure Regulator from FreshWaterSystems.com. It's small, works well and can be installed on the input line to your RODI unit.

 

[Buckeye Hydro]

Just wondering if anyone else has had problems with RO membranes failing in 2-3 months.

I have tried 2 different brands of membranes and carbon blocks. The system started out getting the correct decrease in TDS (about 375 down to 5) but after a few months the TDS starts rising and flow increases. This would indicate that there are holes forming and not the filter getting clogged. Pressure is about 60psi from the town of Owego. I use it for top off, water changes and drinking water. Its hard to believe I am using 10,000+ gallons in 3 months and depleting the carbon block but that is the only thing I can think of.

Has anyone had a similar problem or an idea of what I am doing wrong?

Thanks

Both membranes may have been just fine. I suspect you have an internal crack in your RO membrane housing. Feel free to give us a call when you are in front of the system.

Russ

 

[Buckeye Hydro]

I did have some problems with the original unit I had, but doesn't sound quite like the problem you are having. On my unit, the ratio of product to waste water was never right even after getting a replacement membrane. My DI Resin was being used up very quickly. After switching to a BRS 6 stage unit and getting a pressure valve to reduce my water pressure to 50 psi things are going great.

The only thing I can think of would be to check the chlorine level in your product or waste water. If your carbon blocks are getting depleted, I believe that the chlorine can damage your membrane.

That ratio is controlled by a little $4 piece called a flow restrictor. That's what needs to be adjusted. If you have more than 50 psi available, by all means take advantage of it. Many people have to use a booster pump to get the pressure you're choking off! 100 psi is too high, but 50 is not ideal either.
Russ

 

[Buckeye Hydro]

100 psi will not damage the membrane.

 

[BSamuelson]

Thanks Russ, The first time I thought it could be something with the hardware and I did have a crack between the sediment and carbon canisters so I bought a new system. Still had the problem. Now, with the new housing w/pressure gauge I can see 115psi and it was still increasing when I turned it off.

New pressure reducing valve for the house is set to 75psi (max adjustment) and the membrane now sees 65psi when producing water and 75psi when off. I would like to get it up another 10psi but it will be nice not buying new filters every 3 months, I hope!

It looks like 80psi is the max/desired pressure for most membranes, is that correct? Does anyone publish membrane life vs pressure. I would think anything above 80psi starts to shorten the life of the filter, 80psi=2yr / 100psi=1yr / 120psi=3months?

 

[Buckeye Hydro]

Filmtec membranes were rated to something around 300 psi - so you're no where near anything that wil bother the membrane. Filmtec lowered the membrane pressure rating a while back, but I was told that was not to protect the membrane, but to protect other system components.

80 psi is the max recommended residential water pressure by the UPS (Universal Plumbing Code). You have to be concerned about your prefilter housings as they are seeing the high pressure too. With a booster pump you can crank up the pressure after the prefilter housings to protect them. If you have good housings they will be rated to 125 psi - but I wouldn't push that issue, especially with clear housings.

Russ