Galvanized fittings

Max Boiler

Where is it written that galvanized fittings and pipe should not be used in Hydronic systems? I need to have it in print. I know about the electrolysis, dielectric gasket degradation, galvanizing flaking, zinc glycol reaction, etc. But where is this info in black and white? I know that I read an article once somewhere that covered all of these problems, but my memory of where this info was located has disappeared. Could not find in Dan's books, John Siggy's manual, RPA Radiant Basics, Pipefitter's manual, Ipex design manual, Wirsbo design guide, Burnham Heating Helper, Wall Archive, etc. Anybody got any ideas? Thanks, Max

Dice

galv ftgs

closed loop system?
tell me more...
if in fact system is closed w/ all metallic tubing , galv. should be fine or better than fine.

Mike T., Swampeast MO

I should have taken a picture! Found two galvanized pipes in a converted gravity system. They had been added about 20 years before when a radiator was relocated.

The 1" galvanized was so internally corroded that the passage was maybe as large as a kindergardeners pencil. All of the rest of the system (black iron from about 1922) showed only minor pitting and scaling.