corrosion at fittings where copper contacts black iron???

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 pipe..now 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????

You pretty much answered your question.

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

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

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.