Byou are going between brass and brass.
I would use a brass nipple.
I've been lurking these forums for a while now and am very impressed with the wealth of information presented! Now it's time for me to ask for some advice.
I had a new boiler installed about 4 years ago and recently have noticed one nipple that is starting to rust out. The nipple is between the backflow preventer and what I believe to be a pressure valve. The nipple at the bottom of the pic is connected to the hot pipe coming from the boiler. See the attached pic.
Should I replace this with a dielectric nipple to avoid anymore future corrosion?
What I find interesting is the nipple below the "pressure valve" doesn't show any signs of the similar corrosion.
Thanks for the reply.
Of course it needs to be brass . . . I don't know what I was thinking!
Must have been the previous thread that got me thinking about dielectric fittings.