Heating system black coating

Discussion in 'Boiler Forum' started by jorchard, Sep 12, 2009.

  1. jorchard

    jorchard New Member

    Messages:
    2
    Location:
    wisconsin
    My hot water heating system pipes are all coated with a black inky substance. When the pipes were removed yesterday, the demo crew spilled the black stuff on everything and it doesn't want to come off. The 87 year old pipes are in great shape so I don't think it's corrosion. Is the black stuff a bacteria residue? Is it harmful? Thanks.
  2. zl700

    zl700 DIY Senior Member

    Messages:
    237
    Location:
    Texas
    Probably soot
  3. flamefix

    flamefix New Member

    Messages:
    71
    Location:
    Exeter, England
    scrape some of the black stuff into a clear bottle and dilute with water shake to distribute and then take a magnet and place it on the bottom of the bottle or inside the bottle. If it attracts all the black stuff out of the solution then it is corrosion.

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