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SS circ and brass flange?

JPL941 Member Posts: 51
Hello everyone. Long story short I have a combi boiler with near boiler piping that is a mix of copper and black pipe. I have two taco cast iron circulators with two zones. Initially both zones were onix pipe and I now have one oxy barrier pex (ran new line because it was undersized) and one onix line - radiant bathroom floor. Four years ago I noticed the circulators there were humming and a plumber came in and replaced them- both of them just about rusted shut. 4 years later, just about rusted shut again. I swear it’s the onix. I just tore out all the black pipe (lined with rust) and changed it to brass. I ordered two taco stainless steel circulators. And yes, I do use inhibitor.

Regarding the stainless circulators, is it ok to use my existing brass flanges with the full size gasket or should I used the stainless that came with them? I’d prefer to keep my existing flanges because they’re webstone but I was concerned about the dissimilar metal issue.

Thank you for your help.


  • kcopp
    kcopp Member Posts: 3,996
    Yes its the Onix tubing.... you are fine w/ the SS and brass.
    Which inhibitor? I actually find the Rhomar works better on the Onix tubing.
  • JPL941
    JPL941 Member Posts: 51
    Sentinel x100, it’s what WM recommends for the aqua balance. What rhomar product do you use?
  • kcopp
    kcopp Member Posts: 3,996
    The 922. Seems to keep the Onix demons at bay better... the less in your system the better.