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Steam swing joints

Not much of a steam contractor (alot of hot water jobs), but have one to quote this week end. Weil McClain Tech line talked about swing joints? exactly what did he mean? i have heard that you install an elbow directly above the boiler. is this to stop water hammer or this case steam hammer? The proposed new steam boiler is a weil mcclain EG-55- P. your comments will help me get this job + get it installed correctly. it has 2 inch blk with 2 Supplies off the top and 2 Returns, (one on each side low). Also, i want to install a mcdonald miiler 51-2 low water cutout with boiler water inlet feed. any tips on getting this in correctly. do they not have one inch piping?


Bob Borders


Bob's Heating west point Ia 52656


  • crash2009
    crash2009 Member Posts: 1,484
    The swing joint

    is an elbow just like how you describe.  The purpose is to swing or flex with the expansion and contraction.  If swing joints are not installed, the flex is directed at the gaskets between the sections of the boiler.  Here is the link to the manuals. 


    Mine is an EG-55.  I wanted easy maintenence and dry steam. The drop header would likely make your bid too high, however offering it as an option, might entice the decision maker.  http://www.heatinghelp.com/forum-thread/142897/Maintenance

    The biggest favor you can do for this job you want, is to install the correct size of boiler.  What is the EDR of the building the proposed boiler will be going into? 
  • Paul48
    Paul48 Member Posts: 4,469

    There's a lot more involved with replacing a steam boiler than just putting a new boiler in. You have to address problems and deficiencies that already exist in the system. It requires a sit-down with the customer to discuss any current problems.Then, you have to be able to identify their causes.You're opening yourself up for a lot of headaches, if you don't. You have to educate the customer also. They believe when you are done their system will be perfect, and it will be, but not with a new boiler alone.
  • nicholas bonham-carter
    nicholas bonham-carter Member Posts: 8,576
    New job

    Measure the edr of all the radiators to select the correct model of boiler. If the boiler is too big or small, there will be problems.

    Follow the boiler piping instructions to the letter of piping sizes and layout. Make sure the dry returns drop down to the floor below the waterline.

    Put on new main vents, and enough of them too let the air out with no resistance.

    Even though it runs the cost up a bit, put on a vaporstat to keep the pressure under 1psi, verified by a low pressure gauge, (gauge store.com--0-3 psi.

    Show the customer how to clean the boiler through the skimming port, which could take hours, otherwise you will be doing it yourself. Don't substitute any chemical products for this, and only have pure water in the boiler.

    You will love this project but be prepared!--NBC
  • Hap_Hazzard
    Hap_Hazzard Member Posts: 2,846
    Wen you say "directly above"

    I'm not sure if you mean straight up from or immediately above, but you should always try to make your risers go vertical to at least 24" above the maximum water level before installing an elbow. This prevents carryover from reaching the header and helps to provide dry steam even without a drop header. When there isn't enough headroom to do this, that's when a drop header is really critical.

    The reason swing-arms are critical on a WM EG is that they use elastomeric gaskets between the sections. I have a Peerless G-561 that was piped without swing-arms and somehow managed to survive that way for almost 30 years. I think the only thing that saved it was that the sections are connected by steel push-nipples. That and a lot of luck.
    Just another DIYer | King of Prussia, PA
    1983(?) Peerless G-561-W-S | 3" drop header, CG400-1090, VXT-24
  • SWEI
    SWEI Member Posts: 7,356
    edited October 2012
    Time to hit the books

    Buy this http://www.heatinghelp.com/products/Steam-Heating-Books/25/68/Lost-Art-Of-Steam-Heating  Read it.

    Come back with questions.

    While you're waiting for the book to arrive, watch this http://www.heatinghelp.com/article/107/Steam-Heating/118/Steam-boiler-near-boiler-piping
  • nicholas bonham-carter
    nicholas bonham-carter Member Posts: 8,576
    edited October 2012
    Did you get the job?

    And did you follow all the advice?

    Is this a 1-pipe or 2-pipe system?

    How did the old boiler fail?

    Even if you do not get the job because you were the higher bidder, you can always get called in to clean up the mess left by someone else, so read those books!

    We're here to help with the finer points, beyond what we have already suggested.--NBC
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