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Staple up PEX turning black

styxplo Member Posts: 54
I'm noticing that my PEX seems to be turning black. I installed this about 9 months ago. It was commissioned at the end of the season last year. I flushed it with new system cleaner then filled with mostly distilled water a small amount of spring water to get the hardness within the range of the boiler specs. the system has embeded, staple up, and 3 radiators. Is this something I should be concerned with? Thanks


  • STEVEusaPA
    STEVEusaPA Member Posts: 6,505
    The pex is turning black. How about the water when you flushed it?
    O2 pex?

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  • schultzey11
    schultzey11 Member Posts: 31
    Yikes, working on commissioning my own system soon. What brand is the pex?
  • mikeapolis
    mikeapolis Member Posts: 46
    Sounds like it may not be oxygen barrier tubing. What brand did you use?
  • styxplo
    styxplo Member Posts: 54
    The water was pretty clear when I flushed it. There was a little bit of small particles which I'm guessing was bits of PEX and solder residue. It's Sioux Chief O2 barrier type A PEX.
  • hot_rod
    hot_rod Member Posts: 22,334
    That is not uncommon. It is tough to keep hydronic fluid crystal clear.
    Was the system cleaned and flushed of pipe dope, solder flux, cutting oils, etc? That can contribute to coloring of the fluid.

    Even so the ferrous metals will cause the fluid to color.

    i like to add hydronic conditioners, after the clean and flush. So the color you see is doing good things in the system :)
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • kcopp
    kcopp Member Posts: 4,444
    That will tend to do that w/ a cast iron block boiler and ferrous piping.
  • SuperTech
    SuperTech Member Posts: 2,199
    Maybe use some 8 way boiler treatment and install a Dirtmag.