For a basic RO I think they work well. I only have a 250 which started as a gas unit, but I later got electric in the sugaqrhouse so I converted it to electric. I can take 2% sap to 7-8% concentrate fine. I then run it thru recirculating from the head tank and back into the head tank. The best I routinely get is to 12% sugar. That second pass removes less permeate than the first pass.
To use it I run at 275 PSI on the first pass, on the second pass I run at 240-250 psi. The pressure will gradually climb and I turn it back to those settings. I have goon higher a few times, but I didn't like that. One time I was recirculating while I was doing other things around the sugarhouse and it shut down on high pressure after having turned it back a few times. That time I had 18% concentrate, but I had to run a cold permeate rinse before I could RO any more sap, the membranes were fouled. My unit has 2 membranes at 4" x 40", yours likely will be Ray's newer version with 1 membrane at 8" x40".
If you would like a copy of my reprint of Ray's hand written manual send me an email requesting the manual to dave@cnymaple.com
I have been using this mine since 2012. Just clean the membranes properly and it will serve you well.
I do not depend on the feed pump on mine, I get better performance using a SS 1 hp electric pump. The electric pump feeds the feed pump on the RO, that works best for me.
Dave Klish, I recently ordered a 2x6 wood fired evaporator from A&A Sheet Metal which I will be converting to oil fired
Now have solar, 2x6 finish pan, 5 bank 7x7 filter press, large water jacketed bottler, and tankless water heater.
Recently bought another Gingerich RO, this one was a 125, but a second membrane was added thus is a 250, like I had.
After running a 2x3, a 2x6, 3x8 tapping from 79 taps up to 1320 all woodfired, now I'm going to a 2x6 oil fired and a 200-425 taps.