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Piping 2-Pipe Steam Radiators

I have a project where I have to install some new (used) 2-pipe radiators in an old Dunham system with traps. The original existing radiators all have the inlet at the top (as normally seen), and the outlet mostly on the same side, but sometimes opposite side, at the bottom.

The replacement radiators do not have top inlets. Seems to me if I pipe the inlet at the bottom, the condensate will drain into the supply, rather than leave via the trap/return condensate line. But the customer states they have another two pipe building with traps where all the inlets are at the bottom. Thoughts?
New England SteamWorks
Service, Installation, & Restoration of Steam Heating Systems


  • JohnNY
    JohnNY Member Posts: 3,195
    I've got bottom original supply-and-return tappings on a couple of buildings I service in NYC as well. Unless someone says otherwise, I'd not give it much thought. Give each radiator a pitch of 1/20 of an inch per foot toward the return and I'm sure you'll be fine.
    Contact John "JohnNY" Cataneo, NYC Master Plumber, Lic 1784
    Plumbing in NYC or in NJ.
    Take his class.
  • gerry gill
    gerry gill Member Posts: 3,070
    could also use a concentric reducer for inlet and eccentric reducer for outlet.
    Serving Cleveland's eastern suburbs from Cleveland Heights down to Cuyahoga Falls.

  • Kahooli
    Kahooli Member Posts: 112
    Or eccentric on both, just at opposite positions. Though that probably costs more.