I had a new boiler installed with a closed loop system. Is it still necessary to have a dielectric connection between the copper and steel pipes?

I had a new boiler installed with a closed loop system. Is it still necessary to have a dielectric connection between the copper and steel pipes?

Yes! Dielectric unions,(see image) and used to join two dissimilar pipes together to prevent electrolysis. I have put up a link to a tutorial that may be helpful. Good luck, Tom
Installing A Dielectric Union To Join Galvanized And Copper Pipes - Plumbing System Components (http://www.hammerzone.com/archives/plumbing/systems/components/union_de/intro.htm)