hooking mutilple 4040 reverse osmosis together

Discussion in 'Water Fed Pole Window Cleaning' started by peter rogers, Mar 5, 2015.

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  1. peter rogers

    peter rogers Grand Master

    Feb 24, 2015
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    hi can anyone shed light on this situation of hooking 2 or more 4040 ro up together ive read a few threads on here but stilll no wiser

    1 looking to see what way its hooked up

    2 need more pure water faster

    3 wen it comes outta 2 how much waste is returned

    any help would be great
  2. spruce

    spruce Grand Master

    Jun 4, 2012
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    #2 spruce, Mar 5, 2015
    Last edited: Mar 5, 2015
    You can either link them in parallel or in series.

    In parallel means that you split the water pipe from your prefilters into 2 and fit them to the inlets of both 4040 housings. Join the two waste outlets together and then put a gate valve on the single pipe after the join so you can throttle back the waste on both membranes. Obviously join the pure outlets together and run the single pure line to your di vessel or holding tank. (I prefer a gate valve as I drill a small 1 mm hole through the brass 'shutter' to ensure that I can never completely shut the valve by mistake and damage the membranes.)

    The most common way to join housings together is to put them in series.
    The main hose from your prefilters goes to the inlet of the first housing. You then pipe the waste from the first housing to the inlet of the second housing. The waste of the second housing has a gate valve (or ball valve) so you can throttle the waste back. The pure outlets from both housings need to be joined together and then the single pipe either goes to the di or to the holding tank.

    I would prefer the first method as both membranes get an equal tds input. If you join them in series the second membrane works harder as it has to deal with a higher tds input than the first membrane has to. (Our tap tds is quite low at 120ppm. The waste water after the membrane is around 160ppm if my memory serves me.)

    You need plenty of water pressure and flow to run 2 x 4040 membranes.

    I can't answer your 3 question. Our waste goes off to the drain. There is some system - I think Ionics has it (Roback?) which does allow some of the waste water to be reintroduced into the feed line, but I don't know how it works. What it does mean that the r/o membranes will take even more of a hammering, but I guess its all about balancing membrane replacement costs with water costs.

    Lee Pryors has/or had this as part of his filtration unit.