[StirCrazy]

Originally Posted by reefermadness

NO he mentioned the PRV as something someone could adjust to get your house plumbing at a higher PSI. The PRV is located near you main shut off I guess (still havent went looking for mine). .

ah, ok.. I never had one in my houses. I had to install one in the first house as they jacket the PSI, but my PSI in the second house sucked so I had to buy a booster pump.

Originally Posted by reefermadness

As for the GPD ratings being multiple on Dow membranes, when I look at the dow filmtec membranes are not sold like this. I believe that virtually any ro membrane will produce more GPD when higher pressure is applied. The problems with doing so is that the rejection rating will be affected. If you want rejection ratings similar (I actually find them better) then advertised then you should run them to spec.

DOW never sold them this way, it was a company who was buying dow mwmbrains and relabling them as so many GPD@60PSI and so many @ 90 PSI. the rejections rates are constant through out there operating range as Dow is giving a minimum operating spec. I installed several systems over the last 8 years (comercial and non comercial) so I have had to talk to DOW directly on a few of the aplications and what I got from there engineers was that the rejection rate won't change untill the membrain starts to break down. so if you operate it in a way the is dammaging then you will get degraded preformance. operating at 100 PSI wont cause this, operating at 150 might start to as that is its upper end. at any rate I was confadent running my own at 120 PSI with a high volume pump to suply the water (only had 40 PSI at the second house) so after two years the output was still "0".

Steve