[boxhead]

how do i join galvanzied pipe fitting to a galvanized pipe fitting? and how do i join galvanized pipe fitting (thread) to pvc backflow preventer (female)?

 

[bob22]

how do i join galvanzied pipe fitting to a galvanized pipe fitting?
Depends on what the ends of each pipe are. Typically, these thread together using a coupling or a union, elbow, or tee.

galvanized pipe fitting (thread) to pvc backflow preventer (female)?
a transition fitting

Pictures of the pipes, the backflow device with sizes would help.

 

[Alan]

You have a pvc backflow preventer?? :huh:

You don't want to thread a metal fitting into a plastic female fitting. So if you have 2 fitting ends and 1 of them is plastic, your best bet is to use a schedule 80 nipple.