Reverse Osmosis not making water

[delong_dan]

I have a GE under counter RO system that I can't seem to get more than a cup of water out of per day. (This is after a year of regular use and regular filter changes). After taking the unit apart I found that the water fills up in the first filter cup and goes into the membrane but doesn't pass through to fill up the 2nd filter cup. I assumed my membrane was clogged but I don't know how to tell. I've read postings that say under the counter RO membranes should never clog.

I took the membrane out and tried it and of course the water went right through. Before I spend $70 on a new membrane I'm trying to determine if that is the problem. Do you know a way I could test the membrane ? There does seem to be some rust buildup in it but nothing major.

I also noticed that my little storage tank had very little air pressure. Should I be putting it back up to the 100PSI that is shows on the side of the tank ?

Thanks for any help you can provide me.

[Tom G]

RO membranes usually last about a year before clogging reduces efficiency. Less time if no Water Softener in line before RO.

100PSI refers to how much air or water pressure could safetly be in tank before it ruptures, not working pressure. In use it would never be more than your household water pressure and probably a little less than that.

[Mark Modrall]

Just FYI, I've got a Sears system which has a pre- and post-RO filter sediment catch. Those need replacing once a year or you see a drastic drop-off in production. Sears repeatedly says the RO needs replacing every 5 years, though.

We're coming up on the witching hour; yearly cycle on the particulate filters plus 5 years on the RO. Gonna be an expensive year on the water filter for us :)

-Mark

[delong_dan]

Thanks, It looks like I'll give the new membrane a shot and see what happens.

Tom G wrote:

[Pete C.]

Is your household water pressure adequate? There is a minimum pressure requirement for the RO to reach it's rated production rate. Check the manual and your water pressure.

Pete C.

[Robert Gammon]

the technician who replaced my membrane after 7 years (not Sears) told me that the tank should be pressurized to at least 7 psi, not more than

10 psi. Back pressure on the membrane slows production of water.

[Pete C.]

Right, that's the product tank. I know the RO unit I installed a while back at a previous location had a lot of warnings about it not working with low water supply pressures and the possible need for a booster pump. It apparently takes a fair amount of pressure to get water through the membrane. If the OP's water pressure was near the threshold to begin with and has dropped for some reason they might not have noticed the change, but it could be below the requirement for the RO.

Pete C.