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R.o. system for 2 bay wash

Scott.Downey

Active member
Looking at replacing a old ( probably 50 year old ) r.o. system. Our old one is basically putting out wat that has the same amount of tds as the tap water. Anyone havevany recommend units ? E don't want to break the bank as it's not a hugh seller where we are at.
 
I can't recommend one but could yours be repaired? That is pretty old though. Also, maybe the reason it doesn't get used much is because it doesn't work. (unless it recently stopped working)
 
For a 2 bay SS wash only, you could probably get away with a very simple system with a smaller membrane and a holding tank. Maybe even like a 500-750 gpd membrane would work for you if you have low use anyways.
 
I think we are going to start with a new membrane and work from there. This is the unit. According to our tester the spot free is 149 at the tank and the discharge is 159.
 

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I refurbished an old RO system from 1994 with new membrane, pre-filter, and refilled the existing carbon bed. I put out 4ppm water to a 300Gal storage tank. (starting with 120ppm) More than enough for my 6 bay SS and only cost $200 or so for the Amazon membrane (4x40 inch). Here are a couple pics of what I was working with.
IMG_4044.jpgIMG_4042.jpg
 
Your pump is putting out 110 psi. Nothing unusual there.

A 2540 membrane would typically put out between 650 and 1000 gpd, or 0.45 to 0.7 gpm. Your permeate gauge reads about 0.86 gpm, or 1200 gpd. In other words it is reading too high. Either your concentrate flow gauge is not working, or you're getting no concentrate flow. Not having the proper concentrate flow will trash a membrane in short order. Do you have a needle valve you can turn to adjust the concentrate flow? In an effort to get more pressure, often users that don't know better adjust the concentrate flow much lower than it should be. I'll bet that's what's happened here.

Let's (in this order):
  1. get your concentrate flow adjusted to 1.0 gpm
  2. then check your pump pressure gauge (it will read much lower than it does now)
  3. then check your permeate flow gauge
  4. then check your permeate TDS
Russ
 
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