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Near Boiler Piping Question

Cyclist77
Cyclist77 Member Posts: 107
in THE MAIN WALL

I attempted doing a search but a number of promising posts on this site get an error message. Maybe they are expired because of age?

So for a CI boiler I am trying to determine what kind of pipe material is appropriate for the near boiler. Some articles say copper then some say black pipe for a certain distance. Then switch directly to copper but some want a separation, my mind is blank on the term for this coupling.

So I would appreciate your assistance.

Thanks!

Comments

  • ethicalpaul
    ethicalpaul Member Posts: 7,221
    edited February 10

    Basically: Black pipe above the water line. Black pipe or copper below the water line. I'm assuming you are talking about steam.

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  • jesmed1
    jesmed1 Member Posts: 961
    edited February 10

    Actually, I think you're talking about hot water systems since you've asked questions about radiant floor heating and new hot water boilers. In which case copper is commonly used for near boiler piping.

    Our 2 hot water boilers have all copper near the boilers, then transition into the old large-diameter steel pipes that run to the original cast iron radiators. I think the "separation coupling" you're talking about is a dielectric union, which is sometimes needed to prevent galvanic corrosion between dissimilar metals in the presence of oxygen-bearing water. But in the case of closed hydronic heating systems where the oxygen eventually gets driven out or gets quickly converted into iron oxide, it seems the dielectric unions aren't necessary. All our copper-to-steel pipe joints are simply threaded couplings with pipe dope, and apparently that's standard practice.

    Dielectric unions are needed in DHW systems, though, because the unlimited supply of oxygen in the incoming fresh water will cause galvanic corrosion.

  • Cyclist77
    Cyclist77 Member Posts: 107

    Ethical Paul,

    Hot water. Sorry for not including that.

    ethicalpaul
  • Intplm.
    Intplm. Member Posts: 2,416

    It often depends on how many components that are being piped and what they are made of. Not to mention the preference of the installer.

    A common practice is to have black pipe installed close to the boiler and then have the piping transition to copper and or pex. This can often help with supporting the piping and the structural integrity. This transition can also help with the prevention of electrolysis as dissimilar metals are introduced, ie. black pipe to brass valve to copper, installed one after the other serving the same line.

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