Unless you are running dirt through your water lines (again, which dirt doesn't exactly fall under the term "TDS"), checking the flow without a sediment filter will do very little damage to membrane (and even then, its ability to make product, not waste - unless like I said you have dirt in your lines) if all you do run it for a few minutes - long enough to verify that the pre-filters are not your problem.
Over the last 15 years, I've had my fair share of RO troubleshooting: My current RO is a 50GPD on a well system with high TDS and the last time I changed the membrane was almost 5 years ago. I still get good water quality and good production with this membrane. Whenever production slows I replace the pre-filter (el-cheapo fridge filter) - and about ever other year I run some H202 through it.
A pressure gage won't do anything but verify your tap pressure and if you place it on the south (reject) side of the membrane you will have to block all of the flow and stop flow (it's the flow across the membrane that creates the osmotic effect) - otherwise if you don't stop the flow you won't read any pressure at all.
Based on you not getting any reject water, my assumption is:
1) The prefilters are connected incorrectly, or
2) The restrictor is blocked (unlikely - as whatever is blocking it would have to pass through the outer layer of the membrane to get there), or
3) The entrance to the membrane is clogged.
What I would do:
1) Verify that water flows through the unit without the prefilters.
2) Doublecheck the flow restrictor.
If neither of these work, try cleaning the membrane with H202. If that doesn't work, buy a new membrane.
So - my last word on this topic - after all, all of the various advice your getting may or may not be worth the price you are paying to get it :lol:
- Jeff
