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wet steam from vents of a single pipe system

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sandcreek
sandcreek Member Posts: 8
in THE MAIN WALL
I have a one pipe steam system, boiler installed in 1997, and we have been in the home for about a year.  I have wet steam coming out of most of my vents and have had it last seaon too.  nI know this is wrong as only air should be pushed out.

I have read as much as possible to figure out how to stop it and now I am really confused.

Can anyone suggest what are a few of the most simple steps a homeowner should try 1st to take care of this before I call for a Pro to make a service call?

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  • Steve Whitbeck
    Steve Whitbeck Member Posts: 669
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    vents

    sounds to me like your pressure is set too high. If the pressure gets to 5 PSI it does damage to the vents.

    Have a steam serviceman turn the pressure down and replace the vents.

    also do you have the valves on the radiators turned partially open. If they are not open enough they can trap water in the radiator.
  • kcopp
    kcopp Member Posts: 4,435
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    do you...

    have any pictures? Wet steam is quite often caused by poor piping and Oily/ dirty system water.
  • sandcreek
    sandcreek Member Posts: 8
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    no photos, but....

    No pictures, but I 'll try and describe it

    I can actually see the vapor coming out of the fully opened vent (on the adjustable types) and as it continues drips of water build up on the vent too
  • Rod
    Rod Posts: 2,067
    edited October 2012
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    Spitting Vents

    Hi- Things to check:

    1. Boiler pressure- Residential steam boilers operate at below a 2 PSI maximum. If it is above that the pressure controls needed to be adjusted.

    2. Is the boiler's waterline the correct height? You can find what height it is supposed to be in the installation manual. If you don't have the manual let us know the boiler's make and model # and we can look it up for you.

    3. Check to see that the valve (s) on the steam pipe going into the radiator(s) are fully open.

    These have to operate either fully open or fully shut. Having them half way open causes the steam coming in and the water leaving the radiator to collide, which can cause the problems you are describing.

    4. Using a carpenter's bubble level check to see that the radiators are very slightly sloped towards the steam pipe as this helps the water drain back to the boiler.



    I would highly recommend you get some of the steam books at are offered on this website. The best one to start with is "We Got Steam Heat!"  http://www.heatinghelp.com/products/Steam-Heating-Books/25/61/We-Got-Steam-Heat-A-Homeowners-Guide-to-Peaceful-Coexistence

    It's especially written for the homeowner new to steam and in an evening or two of reading, your knowledge of steam heating will be light years ahead. What you will learn will save you many times the cost of the book!

    You might tell us a bit more about your system.. Names, model numbers or pictures of the radiator's spitting valves might be a help also,

    - Rod
  • sandcreek
    sandcreek Member Posts: 8
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    ok, here's what I did

    awesome help guys



    I actually found out about this site because I have the book mentioned, it is great, but it all sounds good to me, so that's why I figured I'd ask people who know a bunch more than the guy who's only experience is a good book



    so what I did so far....

    1)lowered both the check in and diff. pressures

    2) opened the supply valves on some radiators that needed it

    3)shimmed radiators that need it

    4)replaced all the vents on all radiators



    I'll run the system again, see how things go, and check back on Monday or Tues

    Thanks again for all the advice so far
  • Rod
    Rod Posts: 2,067
    edited October 2012
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    Main Vents

    Hi-  It sounds as though you are on the right track. Glad to hear you have the book,  "We Got.." as we can refer you to a certain page if necessary for an explanation.

    Have you checked that your main vents are of sufficient capacity and are working properly?  For addition information you might want to take a look at this website:

    http://www.gwgillplumbingandheating.com/

    Gerry Gill is a expert steam pro located in Cleveland. His website has a ton of good information on steam heating.

    - Rod
  • sandcreek
    sandcreek Member Posts: 8
    edited October 2012
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    size of main vents?

  • sandcreek
    sandcreek Member Posts: 8
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    size of main vents?

    I will check out the site, but before I go nuts looking at the details, any general suggestion as to the size vent hole for a main vent?  The local plumbing house in my neighborhood sells Dole vents.  (they pointed me toward No. 4 and No. 5 size hole vents for my radiators).  Can something like these be used or is there a specific vent made for the main?

    Thanks again.
  • sandcreek
    sandcreek Member Posts: 8
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    size of main vents?

    I will check out the site, but before I go nuts looking at the details, any general suggestion as to the size vent hole for a main vent?  The local plumbing house in my neighborhood sells Dole vents.  (they pointed me toward No. 4 and No. 5 size hole vents for my radiators).  Can something like these be used or is there a specific vent made for the main?

    Thanks again.
  • Rod
    Rod Posts: 2,067
    edited October 2012
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    Main vs Radiator Vents

    Hi-  Main Vents and radiator vents are two different animals! Main vents are high capacity vents whose job is to let the air out of your steam mains as quickly as possible. Radiator vents on the other had are a lot slower by comparison as there are good reasons not to vent your radiators too quickly. 

       If your system has main vents they should be located on the steam main either right after the last radiator (away from the boiler)  or on the the Dry Return pipe just before it drops down to floor level. (See attached drawing)  If you can't find a main vent look for a plugged tee where they might have been originally installed.

         Each main needs to have its own main vent. If you can tell us the circumference and lengths of your mains we can calculate how much venting you need.

    The commonly used main vents are the Gorton #1, the Gorton #2 and the Hoffman #75.

    Capacity wise:

    1 Gorton #2 =  2 Gorton #1(s)

    1 Gorton #2 = 2 Hoffman #75(s)

    If you can't get them locally Gorton and Hoffman vents can be got from Pex Supply on the internet. http://www.pexsupply.com/

    I'm not all that familiar with Dole vents. I believe their main vents are the #4 and #5 which were good in the days of coal boilers but are way too small for using on a modern boiler.

    . Having large capacity main vents saves fuel as the steam gets more quickly to the radiators.  Let us know the measurements and we can see about getting your main vents straightened out first and then we can tackle your radiator vents

    - Rod
  • Steamhead
    Steamhead Member Posts: 16,868
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    Those vents are too small for your mains

    measure the length and diameter of each steam main and post it here. We'll be able to tell you what you need. 
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Consulting
  • sandcreek
    sandcreek Member Posts: 8
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    main length and diameter

    according to the diagram, looks like I have main vents in the proper locations, but all I can see it their brand (Dole again) but not the size.



    On one side of the boiler I have 20 feet of black 2.5inch pipe and on the other side of the boiler I have 25 feet of 2.5 inch black pipe



    does anyone have any knowledge of what might work best here/
  • Rod
    Rod Posts: 2,067
    edited October 2012
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    Calculations for Main Vents

    Hi -

         The calculations below use the venting tables from Gerry Gill’s excellent venting book. http://www.heatinghelp.com/products/Steam-Heating-Books/25/146/Balancing-Steam-Systems-Using-a-Vent-Capacity-Chart-by-Gerry-Gill-and-Steve-Pajek

    and they are also available in Dan’s book, “Greening Steam”



    Here are the calculations:

    2 ½ inch pipe has a volume of .03 cubic foot per each lineal foot.

            On the 20 ft. main the volume is: 20 x .03 =  0.60 cu. ft.

            On the 25 ft. main the volume is: 25 x .03 =  0.75 cu. ft.

    Venting capacity @ 1 oz. of pressure.

             Gorton #1 =  .330 cu ft. per minute

             Gorton #2 = 1.10 cu. ft. per minute

             *Dole #5 "Quick Vent" = .066 cu ft. per Minute

             * Just for comparison.

    While it is a very good main vent I haven't included the Hoffman #75 as it is fairly pricey compared to the Gortons.

         On the 20 ft. main:

              A Gorton #1 will vent the main in 1.81 minutes

              A Gorton #2 will vent the main in 0.54 minutes

            *A Dole #5 will vent the main in 9.09 minutes

        On the 25 ft. main:

             A Gorton #1 will vent the main in 2.27 minutes

             A Gorton #2 will vent the main in 0.68 minutes

            *A Dole #5 will vent the main in 11.36 minutes

    The theoretical target is to vent your mains in under 3 minutes in which case a Gorton #1 will be satisfactory for both mains. Unlike radiator vents you can't over vent mains.

    If you can't get Gortons from a local supplier, they are available at Pex Supply on the internet. http://www.pexsupply.com/

    - Rod
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