I have a stainless valve I want to install in a copper domestic water line. My concern is: are the two metals compatible? Are stainless steel and galvanized steel compatible?
I presume you have a threaded ss valve. It can be connected to a galvanized threaded pipe or threaded fitting. The ss valve can also be connected to copper pipe by using a male x sweat brass adapter (threaded one end, plain for soldering on the other). Brass will prevent problems from electrolysis. On threaded joints use teflon tape, or in the case where the pipe carries fuel oil, use pipe dope.
I am a bit confused. You ask about nnecting Copper to stainless steel, then ask if Stainless steel is compatible with Galvanised steel. However to join Copper to stainless steel , you will need a special Flux which is only obtainable from a Plumbers merchant. That is if you need to solder them Together. If you dont solder them, Then , yes they are compatible.
How would you plan on connecting them? SS will reject solder and a welding torch will likely melt the copper. Maybe via a PVC piece as an intermediary? If the valve is threaded can you solder a threaded adapter on the copper pipe and use Teflon tape on the threads?
Yes they are compatible. It's common to have underground galvanized service water lines (from the main to the house) connecting to a house main shut off connection which then leads to full copper in the house.
