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Air vent Requirement on Steam Main Line

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Suchitapage
Suchitapage Member Posts: 4
in Strictly Steam

Hello,

I am working on this building (one-pipe system) where I came across this piping arrangement located in the boiler room itself. So the steam header is branched into many main steam lines and one of the lines is shown in the pictures attached.

We can clearly see the steam pipe coming from the right side of one viewing the picture. it separates into two risers and then we can see the condensate lines pitching downwards towards the left. Do we need an air vent on this location? Because I was not able to see one.

Fyi, this building has steam drum in it's distribution system which has steam trap feeding to feedwater tank.

Thank you.

Regards,

20250730_161505501_iOS.jpg
20250730_161508495_iOS.jpg

Comments

  • Steamhead
    Steamhead Member Posts: 17,899

    Can we get some pics of the steam drum and the trap?

    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Consulting
    Suchitapage
  • 109A_5
    109A_5 Member Posts: 2,483
    edited August 1

    I would say , in general, no you don't need it there. Although it may not hurt depending on the length of the horizontal main, better venting may get the steam to the radiators faster. The pipe going off to the Left is just a drip for the horizontal main and condensate return for the risers (one pipe condensate return).

    I would say you do need a main vent at the top of each riser if they do not already exist.

    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
    Suchitapage
  • Suchitapage
    Suchitapage Member Posts: 4
    https://forum.heatinghelp.com/discussion/comment/1861363#Comment_1861363

    Sure. I have attached it below. This building has steam traps but it's a one-pipe system (all the radiators are one-pipe)

    20250730_153304441_iOS.jpg
    20250730_153306310_iOS.jpg
  • JUGHNE
    JUGHNE Member Posts: 11,471

    The first picture looks to me like a feeder pump to return cond water to the boiler.

    The second picture looks like a drop header with the drip F&T trap going into the feeder pump tank.

    You may have a one pipe system and are the traps you refer to the ones at the tank?

    I would call them end of main float & thermostat (F&T) traps going into the tank also.

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