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What is the advantage if any

Hollis Member Posts: 105
Of a 2 pipe steam system?

They seem more complicated? Or is it I'm not used to dealing with them?

Any pro and cons to two pipe systems?


  • Jamie Hall
    Jamie Hall Member Posts: 15,741
    It may be

    that you are not used to dealing with them.  Both types of systems have their advantages and disadvantages.

    One pipe steam can be a little easier to control in terms of balancing -- adjusting the venting rate on the radiators.  On the other hand, two pipe steam can be balanced by adjusting the valves themselves on the radiators.  Take your pick...

    One pipe steam uses less pipe, usually.  On the other hand, it usually requires bigger pipe.  Take your pick.

    One pipe steam requires vents on each radiator and main vents on the steam mains.  Two pipe steam only requires vents or crossover traps on the steam mains, and if the latter only main vents at the boiler.  Take your pick.

    Two pipe steam can run on absurdly low pressures; one pipe generally requires slightly more pressure.

    In my humble opinion, one pipe steam (particularly counterflow) is a little more subject to water hammer than two pipe -- but they can both make a horrible racket if things aren't piped and pitched right.

    And so on...
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
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