After many years, my R.O membrane needed replacement. It went from 1.5 gpm to 3.5 gpm instantly. Bit's of the membrane were found in the storage tank. The TDS was at 90 in the storage tank. I installed a new membrane. When I first pressurized the new membrane it was flowing at 3 gpm@170 psi. I let it sit overnight and tried it again. This time it flowed at 2gpm@170psi. After a couple of days I checked the storage tank and it was at a TDS of 20. But today I noticed the membrane flowing at 3gpm@170psi. The output TDS is reading 70. I'm not sure what's going on. Has anybody else had this happen, where higher than expected flow was measured, with high TDS ?
R.O problem with high membrane flow
- Thread starter celica
- Start date
I'm pretty sure I found the problem. I remembered that when I took the old membrane out, I noticed the O ring in the cap was partially dislodged. I put it back in the groove and then installed the new membrane. When I woke up at 2:30 this morning I had a hunch that the excessive flow rate and high TDS was water partially getting past the membrane. This morning I pulled the cap off and found the O ring was partially out of the groove again. I grabbed another O ring and installed it, and things are running normal. It was untreated water getting past the O ring and causing high "flow" and high TDS readings. The old membrane that I took out is most likely fine. I will look at putting some adhesive in the O ring groove to keep the O ring in place if this happens again. This O ring is hit with 170 psi when the pump starts up.
