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Black particles in water: Navien tankless water heater to blame?

cry1130
cry1130 Member Posts: 1
in Water Quality
Small black particles started appearing in our water a few weeks ago. Appears to only be the hot water. We have a Navien tankless water heater. I'm not sure the model but have attached a picture of the inside. Looks relatively new (we bought the house a year and a half ago). We had the Navien flushed/serviced. Did not fix the issue. We had the valve on the main water line into the house replaced as recommended by a plumber (in case rubber is the issue). House has copper and PVC pipes. No visual evidence of flexible/rubber lined piping in the home. We're not sure exactly what the particles are. I have attached a picture. They smear when you rub with your finger. Any ideas as to what this is and how to fix it?

Comments

  • Intplm.
    Intplm. Member Posts: 2,165
    Those particle are very hard to see. Are you sure the particles are only coming from the hot water ?

    It could be that the hot water is extracting those black particles out of the water when the water is heated. The thing that I can't tell is how they smear when rubbed.

    A few questions.
    Have you had your water tested?
    Is there a water filter and water conditioner on your water main?
    Is this city water or a well?
    From what water faucet did you take the sample from?
    It could be normal build up coming through your faucets that is built up in the faucet aerators ?

    Maybe remove and clean the aerators on your faucets ?

    Try draping a white cloth like a handkerchief over a glass and turn the faucet on drawing water through the cloth? Then look at the cloth.
    Hope these things help. Please respond back.

  • Alan (California Radiant) Forbes
    Alan (California Radiant) Forbes Member Posts: 4,212
    edited February 2019
    Our local water department changed the disinfectant they add to the water from chlorine to chloramine (a chlorine/ammonia compound). The ammonia breaks down rubber, affecting various parts of a plumbing system (toilet flappers, faucet/water heater connectors, etc.); symptoms are like yours. Chloramine resistant fittings are now available.

    What part of the country do you live in? Check with your water department.
    8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour

    Two btu per sq ft for degree difference for a slab
  • Larry Weingarten
    Larry Weingarten Member Posts: 3,576
    Hello, If you have any braided stainless flex connectors, they often have a black rubber lining that disintegrates just as you have described. An expansion tank could be another source of rubber too. ;)

    Yours, Larry
    Intplm.CanuckerFredoSP
  • luckyroy2070
    luckyroy2070 Member Posts: 5

    Hi cry1130, we have Navien water heater and having the same issue as yours. Can you please help me letting know what the issue was and how it was fixed ? It would be huge help as we are in great stress due to this issue. Thank you.

  • Greening
    Greening Member Posts: 36
    https://forum.heatinghelp.com/discussion/comment/1553825#Comment_1553825

    Who promoted those chemicals, the local plumbers union?

    The insurance companies are going to have a field day. . .or rather a flood day.

  • Jamie Hall
    Jamie Hall Member Posts: 24,696
    https://forum.heatinghelp.com/discussion/comment/1810256#Comment_1810256

    No. The public health people. The objective of the exercise is very simple: keep enough disinfectant active in the system, even at the far ends of the system, to kill any bacteria which might get in there. Such as cholera, typhoid, Legionnaires', assorted other nasties.

    Chloramines are one choice. Chlorine (sometimes as a gas, sometimes as sodium hypochlorite) is another. Which to use depends partly on cost, partly on operating safety (chlorine gas is toxic, of course — but sodium hypochlorite is a powerful oxidizer, and is a real fire hazard; chloramines are pretty safe to handle), and partly on source water quality (some source waters react to make bad tastes or odours with chlorine, but not with chloramines).

    If there were no possibility of contamination after leaving the treatment plant, then ozone, or ozone in combination with ultraviolet, could be used as a disinfectant. Unfortunately, experience has shown that public water supplies will get contaminated. Not that often, but it does happen, so a residual disinfectant is the only realistic option.

    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • luckyroy2070
    luckyroy2070 Member Posts: 5

    can some please help me with this ? It’s becoming huge issue for us and no one is able to figure out

  • luckyroy2070
    luckyroy2070 Member Posts: 5
    https://forum.heatinghelp.com/discussion/169518/black-particles-in-water-navien-tankless-water-heater-to-blame

    Any update ?

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