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Main Pipe Sizing?

Is there a chart for minimum vs ideal main sizing? I realize bigger is generally better but I've got a quick question.

I have two mains. One is about 35-40ft long and is 2" and has an EDR load of about 115. This one is fine.

The other one needs rebuilding as a couple of radiators have been moved and it is piped very poorly. It is about 30-35ft long and is currently 1.5" with an EDR load of about 125.

It heats okay but I'm redoing some near boiler piping and I'd like to straighten this out. Should I go 1.5" or 2" like the other main?

Thanks guys!

Comments

  • Jamie Hall
    Jamie Hall Member Posts: 24,839
    You really should have a copy of The Lost Art... the answer's in there. However. Is this one pipe or two pipe? It makes a difference.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • AdmiralYoda
    AdmiralYoda Member Posts: 683
    @Jamie Hall Good point! That has been on my things to buy list! It is single pipe, counterflow.
  • Jamie Hall
    Jamie Hall Member Posts: 24,839
    Really should be 2 inch
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • pecmsg
    pecmsg Member Posts: 5,290
    One of the few times “Bigger is Better”!
  • AdmiralYoda
    AdmiralYoda Member Posts: 683
    2" it is!