RO questions

Discussion in 'Water Fed Pole Cleaning' started by heyoh, Mar 30, 2015.

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  1. heyoh

    heyoh Active Member
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    #1 heyoh, Mar 30, 2015
    Last edited: Mar 30, 2015
    Recently I purchased one of these:

    [​IMG]
    http://www.daqua.co.uk/ro_systems.htm
    doug atkinson
    4021 with sediment+chlorplus10 prefilters

    1. Will it cause any problems if pure outlet is physically lower than inlet on the tank?
    2. How do I know what is the best ratio of pure/waste?
    3. After backflushing how do I find this 'ratio' again easily? Do I have to measure water from waste and pure every single time?
    So far while testing I got:
    600ml waste to 150ml so that's 1 pure to 4 waste - if i'm correct
    turning the valve and reducing waste didn't give much more pure, so I'm guessing that this will be the efficency I will have to live with...
    My tap TDS is ~300ppm, pressure is about 40psi (before prefilters)
     
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  2. spruce

    spruce Grand Master
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    #2 spruce, Mar 30, 2015
    Last edited: Mar 30, 2015
    I use an inline tds meter, also available from Doug.

    Some have a brass T piece on the waste outlet. They have a gate valve as the throttle and the other, probably a ball valve is a bypass around the gate valve. Both will join back after the valves with a 1/2" barbed T piece and head off to waste. With the ball valve closed slowly throttle back the gate valve so you have the sweet spot, ie; the r/o performing at its best. If you haven't an inline tds meter, then you are going to have to take random pure samples and test them with your tds meter. Once you get the best pure output mark the valve handle.

    To flush you would just open the ball valve and close it when you are finished.

    For us our 4040 works best with a 50/50 waste to pure output ratio. But our water tds is around 115 to 125ppm so we can get away with this. Some have said that they need to have a higher waste to pure ratio with a higher tap water tds to help with membrane longevity but you have to balance that against the extra cost of water if you are on a meter.

    Our tap water pressure is now 50 psi and we use an hf5 membrane with no booster. At 40 psi you may need to consider a booster pump provided you have a good volume of water, especially if you have an hf4 membrane.

    It won't make any difference if the outlet of the r/o is lower than the holding tank - within reason of course. Our r/o is on one side of the garage. The garage is joined onto the side of our house on the same wall as the downstairs bathroom, so it was easy to tap into the cold water pipe to the toilet under the floor for a water source into the garage. The IBC tank is on the other side of the garage and the supply hose is attached to the rafters and 'drops' down to a fitting ontop of the tank.
     
  3. heyoh

    heyoh Active Member
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    Thanks for that spruce.
    The way I understand what you say is that I would have to divide the waste line, have to valves, the gate valve would serve to keep the 'sweet spot', and the other one for flushing only?
    What's the cheapest way to do this?

    I also bought a water meter so I can change prefilters accordingly:
    http://www.ebay.co.uk/itm/221584258...49&var=520443321977&ssPageName=STRK:MEBIDX:IT
    This one leaked a lot on both sides even though I used ptfe tape like on all other connections.
     
  4. spruce

    spruce Grand Master
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    #4 spruce, Mar 31, 2015
    Last edited: Mar 31, 2015
    Yes, this is the way to do it using 1/2" BSP pipe fittings.

    http://www.cotswoldengineeringsupplies.co.uk are a good company to buy from, but you will have postage charges added on at the end.

    A410-1/2 BSPT 1/2" male T piece.
    B/V2090-08 BSPP 1/2" female ball valve. (I can't see a blue handled valve.)
    B/V2155-08 1/2" BSPP gate valve (which I suspect you may already have so may not be required)
    2 only BMH 08/08U 1/2" to 1/2" male hose tails.
    ptTJN-12 1/2" hose T piece. Plastic is also fine.

    I/2 hose to suit and some hose clips.
    Use Loctite 648 as a thread sealer. This will allow you to position the fittings and valves in exactly the right place and seal the thread to prevent leaks. The male thread of the T piece screwing into the r/o housing should still be sealed with PTFE tape.

    Loctite 648 is expensive and should be put on the male threads only. Don't be tempted to go for Ebay suppliers who decant and sell cheaper smaller amounts. Go for the McCoy. It also does have a shelf life.
    If one of the threads is a taper (which I have included in the shopping list, then Permatex thread seal should be ok. Its doesn't work if both are parallel threads.)

    CAUTION. Check with your supplier Doug as to what threads your r/o housing has. Mine came with NPT threads which is the American equivalent of BSP - same size thread but a slightly different pitch. Ask if a BSPT fitting is ok to use before you order anything.
    Don't over tighten as the housings are plastic and can split.



    Water meter.
    I can't see what those connectors are on your water meter. Do they rely on a male and female taper to seal of do they require a sealing washer?
    In either case the join will be enough - PTFE tape will probably cause a leak.
     
  5. heyoh

    heyoh Active Member
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    Thanks for all that input spruce
    They are 1/2 inch bsp - not sure if tapered :confused: I've never heard that ptfe tape could cause a leak :confused::confused:
    Btw the best tds reading I got was .15 ppm.
     
  6. peter rogers

    peter rogers Grand Master
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    why so hard i brought mine and plumbed it up in to van hook outside tap up and awy u go sediment carbon ro then tank my pure pipe is level with inlet to tank
     
  7. spruce

    spruce Grand Master
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    Then no problem with BSPT male T piece. The female threads aren't usually tapered, they are parallel (BSPP). Please just don't over tighten.

    If PTFE tape is used on mating surfaces that are designed to seal on each other then they can leak. You could use PTFE tape on all of those threads when fitting a bypass flush valve if you want, but there is always to possibility that you could over tighten a fitting to get the right position, so using a thread sealer will seal and lock those threads even when the fittings aren't fully tight but positioned in the correct way.
     
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