RO membranes

[reefermadness]

I find the best flow restrictor to be a ball valve. With a PSI gauge on the input of the membrane you can adjust the ball valve so that the pressure on the membrane is to spec.

The 150gpd may have good rejection rate but needs 65psi to the membrane in order to acheive this. Most city homes will not have this kind of pressure and a booster would be needed. The 75gpd is the most popular membrane because it also has a high rejection rate that only needs 50psi to acheive which is great for most city homes and you would not need a booster to reach 50psi.

[mike31154]

Originally Posted by reefermadness

I find the best flow restrictor to be a ball valve. With a PSI gauge on the input of the membrane you can adjust the ball valve so that the pressure on the membrane is to spec.

The 150gpd may have good rejection rate but needs 65psi to the membrane in order to acheive this. Most city homes will not have this kind of pressure and a booster would be needed. The 75gpd is the most popular membrane because it also has a high rejection rate that only needs 50psi to acheive which is great for most city homes and you would not need a booster to reach 50psi.

Restricting the flow before the membrane is unlikely to correct a problem of mismatched membrane/flow restrictor downstream of the membrane. I could be mistaken, but I'm not sure a ball valve will lower the psi that the membrane sees either, all you do with that is restrict the volume of water available by making the opening in the line smaller, the same psi will still be present. If you're on city water and wish to adjust the water pressure, you may be better off locating the PRV (pressure reducing valve) in your home's plumbing. These are requred by code in most municipalities and I believe the default setting is 50 psi. They are adjustable though, and I've adjusted mine to provide around 80 psi.

[reefermadness]

I never said I restrict the flow before the membrane. The ball valve goes on the waste end of the membrane and the PSI gauge on the input. When adjusting the ball valve you will see the PSI on the gauge go up and down.

Never heard of the PRV before...I will look into that.

[mike31154]

Originally Posted by reefermadness

I never said I restrict the flow before the membrane. The ball valve goes on the waste end of the membrane and the PSI gauge on the input. When adjusting the ball valve you will see the PSI on the gauge go up and down.

Never heard of the PRV before...I will look into that.

Ah so, sorry, I made an incorrect assumption there when I saw the part about the PSI gauge on the input. My bad.

PRV should be fairly near your water meter, just downstream, although mine is quite a ways down and my outdoor tap is plumbed in before it to take advantage of full city pressure for the garden.

http://www.plumbersurplus.com/images...-5734-3809.jpg

[Doug]

Originally Posted by mike31154

Some systems have it integrated into the fitting on the outlet of the membrane housing I think. Mine is quite obvious since it's a combination restrictor/flush valve and installed separately on the waste line. Not sure what your fittings look like, might be marked on the fitting itself if you look more closely. If you don't see anything beyond the fitting on the membrane housing, you might just need to replace that with a new, conventional elbow or something. Good luck.

Thanks Mike. I also have a separate flush valve. Thats why I figured it was in there but dont see something that resembles it, unless its inside the valve.

[hillegom]

My flow restricter is in the waste water line ( tiny insert) just at the waste output of the membrane

[Doug]

Originally Posted by hillegom

My flow restricter is in the waste water line ( tiny insert) just at the waste output of the membrane

Yes, thats where I thought it was. But be darned if I can find it. Still thinks its part of the flush system.

[mark]

in the Aquasafe the restrictor is part of the flush valve, make of your unit?

[mike31154]

I think it's safe to assume your restrictor is in the flush valve, after all, isn't the purpose of the flush valve to bypass the restrictor? Makes sense that it's integrated. Not sure the restrictors in flush valves are easily replaceable though, you might have to replace the whole flush valve unit with one having the appropriately sized restrictor for your new membrane. Otherwise you could simply remove the entire flush valve when the new restrictor you ordered comes in. You could still flush the system from time to time by reinserting the valve assembly, usually pretty painless with the quick disconnect JG fittings. Or just have the restrictor at the very end of your waste line and pop it off to flush. Or a T-fitting with ball valve before the restrictor, there are a number of solutions, as you can see.

[Doug]

Originally Posted by mark

in the Aquasafe the restrictor is part of the flush valve, make of your unit?

I dont recall the name but sure its on one of my cd,s on the proper connect. I bought it from Prairie Reef Supply in Winnipeg, when he was still in business.

Originally Posted by mike31154

I think it's safe to assume your restrictor is in the flush valve, after all, isn't the purpose of the flush valve to bypass the restrictor? Makes sense that it's integrated. Not sure the restrictors in flush valves are easily replaceable though, you might have to replace the whole flush valve unit with one having the appropriately sized restrictor for your new membrane. Otherwise you could simply remove the entire flush valve when the new restrictor you ordered comes in. You could still flush the system from time to time by reinserting the valve assembly, usually pretty painless with the quick disconnect JG fittings. Or just have the restrictor at the very end of your waste line and pop it off to flush. Or a T-fitting with ball valve before the restrictor, there are a number of solutions, as you can see.

Thats sounds like a great idea, since I already order 2 of the 50 gpd from JL. I think thats exactly what I will do. Thanks you for your assistance. You guys are what makes Canreef the best.