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    Two pipe Air vented system (10 Posts)

  • Steve Steve @ 7:59 PM
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    Two pipe Air vented system

    Looked at one of these Friday night
    Must be an early one, the returns are all dry
    I have all of Dan's books just wondering if there's any more reading material Available
    I want to fully understand this before I start
    Steam seems to come up the return first
    Boiler has been replaced about five years ago
    Vents appear to be way undersized
  • Steve Steve @ 8:05 PM
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    This post was edited by an admin on February 23, 2013 8:07 PM.
  • Paul48 Paul48 @ 10:34 PM
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    I read an article about 2 pipe vented systems in the last couple days. I didn't save it, and can't find it again. Damn, I hate that! The only thing I remember is, it was developed for larger systems. To avoid sewer main sized pipes they would have to run to allow for the counterflow in a single pipe.
    This post was edited by an admin on February 23, 2013 10:34 PM.
  • ttekushan ttekushan @ 11:00 PM
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    I've worked with several of these systems.

    I've worked with several of these systems.

    The returns are usually dry until the boiler room. The returns can fill with steam, but really shouldn't until a little later in the cycle.

    Some things to remember about these:

    The returns must NOT be vented;
    The main usually isn't vented in my experience, but if so, its drip must be isolated from the return thru a water seal or float trap (NOT a float & thermostatic);
    The pressure must be low, like no more than 1 lb or so.

    If the returns are vented, plug the vents. If they drop into a vented condensate receiver, then you must trap the return with a float trap (again, no venting!) or a fairly low false water line. [I've plugged the thermostatic element on F&T traps in this situation with great results. But you didn't hear it from me! ;-) ]

    Just look for thermostatic air vent traps that will either "short circuit" the steam into the returns or vents on the return system. Keep the pressure low and you should be good to go. These systems work fine when treated right!
  • Steve Steve @ 9:48 AM
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    Guys thats a great help
    Any comments on the boiler piping
    This post was edited by an admin on February 24, 2013 9:50 AM.
  • JStar JStar @ 10:00 AM
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    It's awful.

    Everything you shouldn't do is displayed there. Welded pipe, low header, bullheaded tees...
    - Joe Starosielec

    Guaranteed performance. Guaranteed energy savings.

    Serving all of NJ, NYC, Southern NY State, and eastern PA.
    Consultation anywhere.
    (Formerly "ecuacool")
  • Steamhead Steamhead @ 2:32 PM
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    Is this

    a 2-pipe air-vent system that was designed that way, or a Vapor system that was knuckleheaded by someone putting radiator vents on it?

    A real 2-pipe air-vent system will generally have hand valves on both the supply and return radiator connections.
    "Reducing our country's energy consumption, one system at a time"

    Steam, Vapor & Hot-Water Heating Specialists

    Oil & Gas Burner Service

    Baltimore, MD (USA) and consulting anywhere.
  • Steve Steve @ 6:51 PM
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    It was definitely an original

    2 Pipe air vented system With dry returns
    I know the boiler pipping is bad But this should not cause steam in the returns, steam should Favor larger pipes, (the supplies) At least that is my understanding
    At least one apartment has been knuckleheaded steam traps installed and air vents removed
    I'm waiting to get access to the remainder of the basement and some other apartments before we do any work
    Thanks again guys
  • Steve Steve @ 6:52 PM
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    Getting full access on Thursday

    I will follow ttekushans Advice Hopefully we can get this sorted out
    Any other thoughts would be greatly appreciated
  • Steve Steve @ 2:18 PM
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    I found three areas where steam can shot circuit between supply and return
    The thing is some of it looks original is there any possible reason for this it makes no sense to me
    Just want to be sure before I drop them below the Water line
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