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Cause of heavy corrosion - mystery

I had a new HE boiler installed in 2016 in my home. Since then I've had some troubling corrosion problems. First I noticed on the 110V elec supply (BX cable) the metal sheathing on the cable (Al) is completely dissolved in about a 3 in long section. There is a semi clear goo where the metal cladding had been.
Also have serious corrosion near one of the boiler circulator pumps where steel nipple connects to brass check valve (then another steel nipple and elbow into 1" copper). Saw today that connection at the valve now has a small drip.
One thing I noted inside the boiler (Burnham Alpine 150kBtu) is it looks like the ignition wire to the main igniter was pinched under a flange during construction. I could not move it. Having worked on high voltage systems in a past life, I know stray high voltage can do strange things and if the insulation is slightly compromised I could have voltage leakage.

Any other thoughts on these corrosion issues (and I don't live near a body of salt water)?


  • mattmia2
    mattmia2 Member Posts: 3,170
    Condensate leaking back in to the armored cable.

    Is the nipple leaking slightly or is the system leaking such that it is having makeup water added?
    JUGHNE Member Posts: 8,375
    The ignitor cable, if grounded even somewhat, would not deliver the spark needed to light the burner. And it is only hot when the ignition cycle is active.

    Matt may have the answer with condsate leak, that is quite corrisive to most things except plastic, PVC etc.
  • Derheatmeister
    Derheatmeister Member Posts: 1,071
    edited June 11
    Could you post some pictures of the areas with the corrosion ?
    Pictures of the System may also help..

  • hot_rod
    hot_rod Member Posts: 14,797
    Also details about what type of heating distribution, is it radiant, radiators, air coils? If any plastic, PEX tubing was used it needs to be hydronic specific with an oxygen barrier.
    Every picture tells a story.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • HomerJSmith
    HomerJSmith Member Posts: 1,304
    What is the water quality in the sys? Anti-freeze? Post some pics.
  • ChrisJ
    ChrisJ Member Posts: 11,612
    "the metal sheathing on the cable (Al) is completely dissolved in about a 3 in long section. There is a semi clear goo where the metal cladding had been."

    Do you have any pictures of this?
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
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