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The A Dimension

Unknown
Unknown
in THE MAIN WALL
condensate pump???

Comments

  • Scot B
    Scot B Member Posts: 26
    The A Dimension

    So here I am installing a replacement boiler in my 150 year old house. Removed a Utica and installing a a wood gun E-250 wood gasification steam boiler. Just bought dan's book the lost art of steam heating. The new boiler is tall and I had my risers sized right + 24" with dropped header. However I just ran across the A dimension. You know 28" minimum between middle of glass gauge and lowest return. By the way I have a one pipe parrallel flow dry return system. New measurement with new boiler is 19", I'm short by ten" What problems will this cause me? and what should I do? Try it as it is, or spend a week and a half without heat this close to fall and dig the floor, pour concrete etc.... please help

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  • Paul Fredricks_9
    Paul Fredricks_9 Member Posts: 315


    There is a slight amount of safety margin in the 28" figure, but no way near 10 inches. What will happen is the condensate will not return to the boiler and will back up in the returns. See this: http://www.heatinghelp.com/steam_waterhammeratthemiddle.cfm

    Others know the answer better than me, but it seems that you may need to start digging. Even with a vaporstat set very low, you won't get away with this one.
  • nicholas bonham-carter
    nicholas bonham-carter Member Posts: 8,578
    \"a\" dimension problem

    could this be solved with a "false waterline"? [shown in dans book]-nbc
  • Paul Fredricks_9
    Paul Fredricks_9 Member Posts: 315


    I think that's for water lines that are too low, keeps a wet return from turning into a dry one.

    I just found out that someone walked off with my Lost Art! Guess I'll have to order a new one. I have a Peerless book on steam. It seems to say that on systems over 100 MBH you can have a 14" dimension A. It does this by allowing only 3.5" for piping pressure drop, instead of 14". I suppose that is due to larger pipe sizes?

    I'm really guessing here. Frank, where are you?
  • DanHolohan
    DanHolohan Member, Moderator, Administrator Posts: 16,600
    A false waterline

    fixes the problem of a wet return that threatens to become a steam line when the new boiler's waterline is too low.

    I would not feel comfortable with an A Dimension that is as low as this one is going to be. The options are a condensate pump, or a pit.

    Sorry.
    Retired and loving it.
  • Steamhead (in transit)
    Steamhead (in transit) Member Posts: 6,688
    Two things come to mind

    Those dry returns are certainly lower than the ends of the steam mains. By replacing them with wet returns, you'd move the "A" dimension to the ends of the steam mains and gain whatever the difference in height is.

    28 inches is fairly standard, but I've run across one-pipe systems with original coal-converted boilers that had lesser "A" dimensions- and they worked.

    In "Lost Art", page 25, we read that a smaller system can probably work with a 14-inch "A" dimension. It's a matter of the system's pressure drop, which determines how high the water will rise in the drips.

    If the radiation load on your steam mains is considerably less than their maximum capacity, the pressure drop will be less, and you can probably get away with a lesser "A" dimension. Paul, you had the right idea here.

    "Steamhead"

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  • Unknown
    Unknown
    Whoops sorry

    Dan I had not read your post!
  • Mark_33
    Mark_33 Member Posts: 5
    A Dimension or B Dimension?

    Are we talking about the "A" Dimension or "B" Dimension?
    Scott said "28" between the water line and lowest RETURN". Isn't the "A" dimension between the water line and bottom of the lowest steam main? The "B" dimension is 30" between the water line and the lowest return line for every pound of pressure inside the boiler. That makes it even worse!
  • DanHolohan
    DanHolohan Member, Moderator, Administrator Posts: 16,600
    Good point

    He didn't say if this is one- or two-pipe steam.
    Retired and loving it.
  • Scot B
    Scot B Member Posts: 26
    success

    Well after much contemplation, pulling my hair out, and general misery I have achieved heat. I was so close to having everything plumbed that I continued without a condensate pump. Tonight the system was fired for the first time, two and a half hours later I had steam from a cold start. No Hammer, no spitting the system is silent and I mean silent. Unlike my past oil fired boiler no clinking, clanking, hissing, banging nothing. The wood boiler worked flawlessly. If it sounds like I'm gushing well I am, this is just fantastic!!!!! I want to thank everyone for their comments regarding my post, your insight is far more than mine. Oh and the system didn't even take on make up water. Now that I'm done being ecstatic I will wait and see what happens. Soon the first cleaning will take place and I'm sure I will be back to the nail biting adventure I was just on.

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  • Steamhead (in transit)
    Steamhead (in transit) Member Posts: 6,688
    How about

    taking some pics and posting them here?

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  • Scot B
    Scot B Member Posts: 26
    Yeah Can do!!!

    I will take some pics of the new system with the 4" dropped header. Will also post one of the previous system so you can pick out what was wrong!!!! Give me a day or two, so I can finally get some sleep with heat.

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