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Hartford Loop

JohnA Member Posts: 7
On a one-pipe steam system with a Hartford Loop on the return, how does the returning condensate (water?) rise vertically through this loop to get back into the boiler? In other words, what pulls the water upwards?


  • Unknown
    edited March 2010
    Hartford Loop

    Hi- The Hartford loop is on the boiler. The idea was that if the return line sprung a leak, the water wouldn't completely drain out of the boiler and cause a possible boiler explosion.

    I've attached a diagram of a one pipe parallel flow steam system. The Hartford loop is composed of the piping labeled "header" and "equalizer" and forms a "loop" coming out of out of the top of the boiler to the "header", down through the "equalizer", and back into the base of the boiler.

    The piping labeled "wet return" is how the condensate gets back to the boiler. As you can see in the diagram, the return line connects to the Hartford Loop at just below the boiler's

    designed waterline.

    - Rod
  • Jamie Hall
    Jamie Hall Member Posts: 22,908
    And it doesn't have to "pull" up...

    as you can see from Rod's lovely diagram, the water in the the vertical pipes connected to the wet return stands at a higher level (slightly) than the water in the boiler -- and that difference in level is enough to push the water through the wet return and back up to the level of the water in the loop.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • JStar
    JStar Member Posts: 2,752

    ....seeks it's own level. Raise the water level in the return, and the water will rise in the loop. The only thing stopping it from returning to the boiler, is the system pressure. That's where the A Dimension and unspent main pressure comes in to push it along.
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