Galvanic corrosion with CSV / PVC bushing leaks

Discussion in 'Pumps and Tanks Well Forum & Blog. Water is life.' started by rmgolob, Mar 8, 2021.

  1. rmgolob

    rmgolob Member

    Joined:
    Dec 16, 2016
    Location:
    Indiana
    In a previous thread, @Reach4 stated:
    "(Brass and stainless) and (brass and copper) are normally thought to not have galvanic corrosion problems."

    I'm not disputing that at all, but....
    "Normally" and "Problems" offer at least a level of concern greater than Zero.

    My house has all original copper from 1976 (45 years old.)
    I'm certainly not concerned about corrosion with a brass fitting connected to the stainless CSV body.
    But I would be concerned that that dissimilar connection could lead to corrosion elsewhere along the copper piping.
    Yes? No? Maybe?

    I say all this because in the pictured set up I have PVC threaded bushings in each side of the CSV. I know why people do not like threaded PVC - A bear to keep from leaking.
    That is the only 2 spots in my installation that leak.
    I suppose I did not tighten the bushing enough, but going into stainless, I figured there was the potential to compromise the PVC threaded into the much much harder stainless.

    My "fix" for the outlet would be to replace the 1" x 3/4" PVC bushing and 3/4" Sharkbite with a single 3/4" x 1 " NPT Sharkbite.
    That would certainly work, but do I then worry about the galvanic corrosion?

    Is it OK to CRANK the bushing into the stainless CSV threads?

    Anyone else experience this?

    Anything else?

    As always, Thanks in advance.

    CSV Bushings.JPG
     
  2. Terry

    Terry Administrator Staff Member

    Joined:
    Aug 17, 2004
    Occupation:
    Plumber
    Location:
    Bothell, Washington
    I don't see brass to stainless as being a problem.
    How tight is the PVC to the stainless now? Maybe snug it up a bit more?
     
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  4. rmgolob

    rmgolob Member

    Joined:
    Dec 16, 2016
    Location:
    Indiana
    Thanks - I THOUGHT it was tight, but perhaps not....
    I'll try that first.
     
  5. valveman

    valveman Cary Austin Staff Member

    Joined:
    Mar 15, 2006
    Occupation:
    Pump Controls Technician
    Location:
    Lubbock, Texas
    Need a good backup wrench to be able to tighten the bushings better. Get them as tight as needed and use Teflon tape with pipe dope on top of that if you want.
     
  6. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    What material is that piece of black-colored pipe?
     
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