Galvanic Corrosion

I searched the boards but didn’t find much regarding galvanic corrosion so thought I would post my question here.

What do you think the likely cause of this galvanic corrosion is from??? I suspect condensate running back down the flue but want someone a little wiser to confirm this or steer me in the right direction.



Galvanic corrosion is caused when dissimilar metals are in contact with one another either directly or through an electrolyte.

What you have is simply corrosion. It could be from condensation or could be from water entry. Why not just report what you know to be factual. i.e., that the vent is corroded?

Chuck’s right and so are you, David. It’s not galvanic, it’s caused by condensation and that white powder is typical evidence of a flue that’s too long, has too many bends, or has inadequate slope.

Thanks Kenton. And Chuck, no kidding, what do you think I did? But thanks for the response just the same.