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3 mains, 1 has no pressure

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jlbk
jlbk Member Posts: 19
in THE MAIN WALL

I have a Weil McLean, where there’s one riser coming out of the boiler and then it splits up into 3 mains. Radiators on one of the mains barely heats up. There seems to be no pressure building in the system. It never cuts out and the pressure gauge never shows any pressure. Is the issue the 3 mains? Is there an easy fix?

IMG_9802.png

Comments

  • ethicalpaul
    ethicalpaul Member Posts: 8,355

    Photos from farther back and with more light would be better.

    You can try slowing the radiators that do get hot in order to send more steam to the ones that aren't getting enough.

    But keep in mind there could be failed vents at play, or sagged suppy pipes, things like that.

    NJ Steam Homeowner.
    Free NJ and remote steam advice: https://heatinghelp.com/find-a-contractor/detail/new-jersey-steam-help/
    See my sight glass boiler videos: https://bit.ly/3sZW1el

    Ironman
  • Ironman
    Ironman Member Posts: 7,886

    Yes, better pics from farther back, please.

    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 11,747

    Are we actually talking a steam boiler here? It does not actually say so. I have this example of a close up picture and asking why does this not work?

    Your persistence… …reminds me of the person that posted this query on a Auto Repair DIY site. They insisted there was a problem with the tire valve because the tire would not inflate.

    Screenshot 2025-11-18 at 9.48.45 AM.png

    Am I not understanding how this tire valve works? I have been adding air to this tire valve for over 30 minutes and the tire will not inflate. Can someone tell me what I'm doing wrong here?

    Screenshot 2025-11-18 at 9.47.55 AM.png

    Then someone asked for a picture from farther back. Now we get the real story. A completely different possibility for the outcome.

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

    Ironman
  • mattmia2
    mattmia2 Member Posts: 15,980

    is this boiler a coal conversion or is that a header from the previous boiler that wasn't removed and re-piped properly?

  • dabrakeman
    dabrakeman Member Posts: 899

    Do you know if you have any main vents? If so where are they and can you send photos of those as well. They should be at the ends of the mains just after the last takeoff to a radiator, or, perhaps they are back closer to the boiler. Take care of @EdTheHeaterMan 's requests first.

    If you have a steam system then a properly working system won't show much if any pressure at all on the 0-30psi gage. Is this a new system to you or has it worked without this issue before and now recently it has the issue?

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