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color of boiler water

I recently commissioned a new system with a Lochinvar WHN111 mod con boiler. It has a Lochinvar stainless steel 30 gallon buffer tank, and a Lochinvar 50 gallon stainless steel indirect. All boiler room piping is copper, which runs to the Caleffi manifolds and then Uponor hePex is run in a home run configuration to some Dianorm wall hung rads. I cleaned the system with Sentinel X300, but I can see through the pex that the water is very orange. Is this normal?


  • Jamie Hall
    Jamie Hall Member Posts: 17,060
    That's dissolved iron. Maybe from the radiators? Do you have any corrosion inhibitors in the system?
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • kcopp
    kcopp Member Posts: 3,819
    How long did you let the x300 run in the system?
  • roundrightfarm
    roundrightfarm Member Posts: 54
    I have currently not added any corrosion inhibitors. There is not much iron in the system, but it could be from the pumps or the radiators. Maybe the brass manifolds and fittings also could cause discoloration? Or perhaps the process of being heated causes some water discoloration as well?

    I let the X300 circulate for about 4 hours with the boiler firing and water temp around 140F and both DHW and boiler pump trading off and system pump on full time.

    Do you think if I drain and flush the system and add a corrosion inhibitor the water will be less orange?
  • kcopp
    kcopp Member Posts: 3,819
    Personally I would have let the cleaner stay in a few days.
  • hot_rod
    hot_rod Member Posts: 15,027
    the O2 in the system will oxidized any ferrous components and tint the water. Dont expect it to stay clear. Conditioners with O2 scavengers and film providers will help limit initial corrosion, and prevent ongoing corrosion as additional O2 enters

    Keep an eye on it, try not to add additional water and O2. Dark red or black water would indicate excessive O2 is entering and rusting components
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream