I'm replacing part of my hot water radiator system that was connected with black pipe. It hung down 8" or so from the basement ceiling and I'd like to run PEX through the joists to get more headroom. I removed the black pipe and left 1" male threaded pipe connected to the radiators. I picked up some brass PEX to female threaded adapters (these).

They fit but as I was putting them on I realized I had dissimilar metals connecting. Should I use a 1" to 1" dielectric union or is there another way to separate these metals? Edit: Or is brass to black pipe not a problem at all?

 

first make sure you buy oxygen barrier pex. Dielectrics tend to fail after a while due to the rubber gasket drying out and failing. I would be more likely to just use the brass adapter without the use of the union. Just my opinion, we will see what the others have to say.

 

The brass adapter is fine but be absolutely certain you use an oxygen barrier PEX.

 

Thanks guys, and I did buy barrier PEX. It think I'm set.