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Thread: Low HW pressure on Tankless System

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  1. #1
    DIY Member gmrules's Avatar
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    Default Low HW pressure on Tankless System

    I have Nortiz Tank less HW system in my house till recently I had good HW pressure, Now when I turn on more than 1 facet have little to no pressure.

    I am on a private well who water is little hard and I do get calcium build up on the show heads and the tiles and the toilets do show the brown / orange stains

    Today I cleaned out the strainer on the cold water inlet to the unit hoping that would be my problem but it was not.

    I am suspecting the heat exchanger needs to be flused and cleaned out with like CDR or something like that to de-scale it.

    Am I on the right lines or completely off base?

    any ideas or feedback would be greatly appreciated

    Thanks
    george

  2. #2
    TROJAN WORLDWIDE SALES RP MACPLUMB 777's Avatar
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    Exclamation Low Hw Pressure



    YES MERRY CHRISTMAS;

    DO NOT USE CRL;


    you need something safe for drinking water, ie; potable water,
    use eather white vinger or AO SMITH sales a food grade acid to flush though
    the heat exchanger this may several passes to clear out the lime buildup

    then flush with clear water a couple times before putting back into service

    JERRYMAC MASTERPLUMBER PH.D WATER HEATEROLGY

  3. #3
    Licensed Grump GrumpyPlumber's Avatar
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    Two other items, check the cold inlet for a screen...you might just have sediment clogging it.
    If the GPM rating is 3 GPM or less, it's the flow restrictor...which means your unit is undersized.
    You should do a vinegar flush at least once a year, depending on your water content.
    "The biggest regrets we have in life are the chances we never took."

  4. #4
    DIY Junior Member gmt's Avatar
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    I concur with the two posts above.

    Additionally, it may be undersized and is compensating for keeping the water temperature at the desired setting. Some of the units will restrict the flow in order for it to get the water warmed up to the required temperature.

  5. #5
    Plumbing Contractor srdenny's Avatar
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    From my experience with Noritz, I'd say it's the screen on the cold inlet.

  6. #6
    Master Plumber master plumber mark's Avatar
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    Talking How old a Nortiz??

    I am not starting trouble here...

    but I would be interested in hearing how hard the water is??

    wether they have a water conditioner or not.??


    and how long has this tankless heater has been installed??


    If the filter is jsut the only problem you will be lucky

    If it needs to be de-limed , then it is something you
    will have to do "every so often"


    that is what I am curious about...

  7. #7
    DIY Senior Member construct30's Avatar
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    Master plumber mark is possibly correct. Fix the problem not just the symptom.

  8. #8
    Plumbing Contractor srdenny's Avatar
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    Deliming with CLR is not too difficult if you have these installed on your heater.
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