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New boiler install one pipe counterflow

Installing new boiler in small house has single pipe counterflow system. The original manifold runs full size 2 in from Supply to return with tees for each radiator. From what I can tell I should add returns just before each radiator connects to the manifold. Is that needed and Do I run those to the floor and tie them into the manifold return. And does it require a Hartford Loop would I be tying the new returns and the manifold return back in at normal Hartford Loop height?


  • nicholas bonham-carter
    nicholas bonham-carter Member Posts: 8,576
    edited October 2019
  • joshvplumbing
    joshvplumbing Member Posts: 3
    Thanks nick. That would be so easy for the situation i have my only question would be is the ones ive seen have had drips from each of the branches just after they tie into the main going to the return. You dont think thats necessary?
  • Jamie Hall
    Jamie Hall Member Posts: 22,934
    No, it's not necessary -- provided that the main slopes either with the steam flow (parallel flow) or, slightly more steeply, against the steam flow (counter flow) and provision is made at the low end for the condensate to return to the boiler.

    Be sure you size the boiler correctly!
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    EBEBRATT-Ed Member Posts: 15,335

    You normally don't need drips in a counter flow except in each main right near the boiler.

    But, for all we know they may have run the counterflow main low end towards the boiler (which would be correct) and made the main undersized. An undersized main will hammer...............so maybe the drips on the branch were part of the original install .............or maybe added later on.

    The only way to know would be to size all the piping from scratch and see what you get