Are dielectric unions used only where copper joins the black pipe or must they be used if after a bronze fitting there is copper located anywhere in the system? I will have black iron 10' from the Garn, then only black iron or brass fittings between the Garn and the pex tubing. I will however have copper 200' at the end of the pex tubing connecting the heat exchanger to the pex supply and return lines.
It seems counter productive to add copper by way of a dielectric fitting which is half copper, and then the copper fitting to revert back to black iron which will continue to the pex. Without additional information is seems better to use an iron fitting and avoid the copper.
It seems counter productive to add copper by way of a dielectric fitting which is half copper, and then the copper fitting to revert back to black iron which will continue to the pex. Without additional information is seems better to use an iron fitting and avoid the copper.