Corrosion at Fittings Where Copper Contacts Black Iron???

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Post Fri. Sep. 21, 2012 10:06 pm

hello all, hooked my boiler up last year , now its gettin cool and we are talkin about heat for the winter,,, a steam fitter on the job and another mason told me that you cant put copper to black iron ,or steel/ said elecltrolisis wil happen and corrod the fittings, the fitter said I should put and electostat ????? union in .. basically a steel nipple out of the boiler then this special union then tne copper is this that serious to worry, and change my set up or not... to change my plumbig I have to shut down , runnin an aa130 24/7 year round ... your t5houghts are apprecieted thank you , tommy I guess I need to know if this corrosion will blow out the fittings in 1 year or 20 yrs????
Last edited by Fran654 on Fri. Sep. 21, 2012 10:17 pm, edited 1 time in total.

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Post Fri. Sep. 21, 2012 10:12 pm

You pretty much answered your question.

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Post Fri. Sep. 21, 2012 11:48 pm

that is a bunch of bullcrap 1st of all it's called a dielectric union , 2nd the only places we ever used them was on gov. & large prevailling wage jobs where a mecanical engineer did the plans &specks , if you ggo into any celler , basement or residential boiler room churches ect. you will find c x m adpts screwed into b/m & ci fittings and they will outlast the boiler AMEN nuff said jim

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Post Sat. Sep. 22, 2012 7:49 am

Unless you are operating your boiler submerged in seawater, I wouldn't worry about it.

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Post Sun. Sep. 23, 2012 12:54 pm

Corrosion occurs when oxygen is present in the fluid. On a sealed hydronic heating system there should be no problem with electrolysis. If you had a domestic water system, where there is a constant supply of fresh water, then di-electric unions should be used between iron and copper pipes.

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