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US Boiler IN12 with 2 pipe vacuum steam built in 1929

We recently replaced a Burnham IN12 from the mid-1980s with a new US Boiler IN12 LNI-LL2 and I believe the near supply piping was installed incorrectly causing the boiler to short cycle.


When the pictures I have posted are compared to page 17 of the US Boiler Installation and Operation manual there is little resemblance between the two and I have been told is the likely cause of my problem. 


I would much appreciate any input or opinions from the readers here regarding the situation. 


  • Steamhead
    Steamhead Member Posts: 15,349
    They must have followed the diagram

    on the page where they tell you what NOT to do. You can't fix stupid.

    This boiler doesn't even have a proper header. They just ran the two pipes up into the existing piping, where the two pipes collide with each other, and put an equalizer connection on the right-hand one. This boiler needs a 3-inch header.

    Go here- the second pic is of a similar type of boiler piped correctly. Notice how the two risers from the boiler connect to the header, after which the steam goes into the system piping and the equalizer drains any water that got up that far:


    And, since you have two steam mains, each main should have its own takeoff from the header. In the following thread, the third boiler had this same problem, and you can see how we fixed it:


    That boiler needs to be re-piped properly. If you haven't given the installers their final payment, do not do so until it's right.
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
  • KC_Jones
    KC_Jones Member Posts: 5,082
    The only thing...

    That could have made it worse was if they piped it in copper.  What comes to my mind is if you basically did a one for one swap how the install was messed up this bad?  What did the previous IN12 look like?  Also are all the problems new with the new boiler?  The installer should have recognized the problems from the start and done a proper install.  Listen to what Steamhead wrote he is one of the best in the business.  Also out of curiosity did the installer measure all your radiators to verify the correct size boiler was installed?  That can also cause issues.  It shouldn't be assumed that what was there is correct.  These boilers are notorious for being over sized.
    2014 Weil Mclain EG-40
    EcoSteam ES-20 Advanced Boiler Control
    Boiler pictures updated 2/21/15
  • RobG
    RobG Member Posts: 1,850

    WOW!  In the words of Forest Gump "That's all I have to say about that"
  • Jamie Hall
    Jamie Hall Member Posts: 18,966
    At least

    the Hartford loop nipple is short...

    Did you notice that they managed to set up the various elbows so that they can't give for expansion?  That does take talent...
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • gerry gill
    gerry gill Member Posts: 3,034
    while i dont know if the short cycling

    Is being caused by the incorrect piping, (and it is incorrect), my gut tells me that since they didn't read the install manual for the proper piping, that they probably didn't skim the boiler several times either. I bet the water is oily.
    Serving Cleveland's eastern suburbs from Cleveland Heights down to Cuyahoga Falls.