Hot water pipes, joining copper to iron
Hot water pipes, joining copper to iron
(OP)
I want to replace most of my existing black iron hot water heating pipes to divide the system into zones. Is it OK to use copper pipes to connect to my cast iron radiaters and to iron pipes? Do I need to use dielectric unions?





RE: Hot water pipes, joining copper to iron
The general consensus seems to be that as long as you're not adding fresh water full of oxygen all the time (bad for a number of reasons), the initial shot of dissolved oxygen gets eaten up in a tiny amount of initial corrosion, then it's gone. I don't know of any tight system that suffers from corrosion where copper and iron/steel join. That's not to say that there couldn't be, somewhere.
RE: Hot water pipes, joining copper to iron
RE: Hot water pipes, joining copper to iron
I agree, the textbooks say there should be corrosion in closed loop systems like this, with copper and iron joined together. But in my experience, it doesn't happen, for whatever reason. The cure (dielectric unions) very much seems to be worse than the possible disease (dissimilar metal corrosion). The dielectric unions routinely leak, fresh water is added as make-up, and then the corrosion game is REALLY on in closed loop heating systems.
RE: Hot water pipes, joining copper to iron
RE: Hot water pipes, joining copper to iron
RE: Hot water pipes, joining copper to iron