RO/DI driving me crazy!!

[OldSalty]

Yes that is true, but why would you want 8:1? your just wasting a lot of water and also throws off the pressures the units needs to function correctly. The flow restrictor that was installed was put there for that membraine. Don't mess with it, just use the unit like it was intended. Get another flow restrictor , put it in and leave it alone, you will be ok. I think you might be trying re-engineer the unit and it don't need that. Measure the TDS at 8 to one then adjust it between 3 to 5 to 1 and measure again, you will see a much lower TDS because an RO membraine needs a min of 40psi to work. So if you open up the drain line all the way the pressure inside the membraine drops. Your basicily bypassing it. Thats the best way I can explain it, which as I hope you can now see thats why you have had so much trouble with the unit. If you have the correct restrictor and you keep your filters changed ofter there is no reason why the membraine won't last 3 or more years. Remember I have been thru 3 membraines because of this, so I know what I'm talkin about.

[Bill S]

Here's the quote from my guy about the adjustable flow restrictors:

"...the adjustable back pressure is a scam....instead of a properly sized flow restrictor, they give an adjustable... guess what... the homeowner wants to save money and turns it either off or to a stetting that is too low...result...bad water and bye bye membrane...great way to create business...."

[OldSalty]

I REST MY CASE!!!

[BuckeyeHydro]

Keep your adjustable restrictor.

Sounds like an easy fix here - I'll bet your RO membrane is not fully seated - pull it out and inspect the small rubber orings at the far end. With a flashlight also inspect the small plastic "cup" into which the RO membrane stem inserts in the far end of the housing. Assuming the orings are ok, and the membrane housing is OK, then simply re-insert the membrane until you feel it hit the far end. Then with the heel of your hand, push hard and turn, and you'll feel to membrane go in another 1/2".

[BuckeyeHydro]

"...the adjustable back pressure is a scam....instead of a properly sized flow restrictor, they give an adjustable... guess what... the homeowner wants to save money and turns it either off or to a stetting that is too low...result...bad water and bye bye membrane...great way to create business...."

My goodness. I don't think there is any business-generating scam going on with adjustable flow restrictors.

Can you adversely affect your system if you don't set it correctly? Sure.
Can you adversely affect your system if you set it wrong purposefully? Sure.

Can you get peak performance out of a system with a correctly adjusted flow restrictor? You bet.

Adjustable flow restrictors are not a good choice for a point-of-use system where the operator wants to set it up and walk away (like a typical drinking water set up under a sink). They can be a very good choice for a hobbyist.

Russ @ BFS

[Bill S]

Sorry, Russ, but I TOTALLY disagree. Just look over these posts, and talk to people about RO/DI systems. Many get disgusted because they can "...never get it working right...". Destroying a membrane and the DI resin just to save a couple of $$ on water? Give me a break. I'll take the non-adjustable every time - and I couldn't possibly recommend the adjustable type of restrictor to ANYONE.

[BuckeyeHydro]

I respect your opinion Bill.

Half the posts above seem to be people having trouble with capillary flow restrictors.

If you have an adjustable flow restrictor, and you want a non adjustable one, that's easy. Never make an adjustment to the needle valve that is an adjustable flow restrictor and viola - you have a static flow restrictor.

A couple of pointers on adjustable flow restrictors: They are inteded for people who understand the systems and want peak performance, especially when the tap water temperatures change through the seasons. They are not intended for people who want to pay next to no attention to their system.

Don't fret about tuning the restrictor to a precise 4:1 ratio. Its not that critical - anything between 3:1 and 5:1 is ok. If you have a static flow restrictor - check the ratio during the dead of winter - you won't have a 4:1...

The idea of an adjustable restrictor is not to save water - it is to keep the ratio at about a 4:1 to maximize production, even when the conditions (in this case water temperature) are far removed from the factory specs (77 degrees F feed water)

If you have one and don't want it, by all means set it at a ~4:1 in the summer and never touch it again (it thereby becomes a static restrictor), or replace it with a static restrictor. They are cheap and super easy to install.

If you install a capillary type restrictor, you can buy one that is pretrimmed for a x gpd system (assuming you have 50 psi water, 77 degree water, and 250 ppm water), or if your conditions don't match factory specs of your membrane, you can buy an uncut capillary restrictor and trim it to length yourself to get your system at an apx. 4:1.

Russ @ BFS

[Bill S]

Wow. With all of the other things I have to worry about, "tuning" my RO units for feed water temperature changes? I have a hard enough time changing all of the dang 9 volt batteries in my smoke detectors on the "spring/forward, fall/back" events!

[BuckeyeHydro]

:lol