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How to Shorten Steam riser?

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RadiatorFan
RadiatorFan Member Posts: 13
in Strictly Steam

I am considering options for replacing a taller radiator (38”) with a shorter one (30”), in my two pipe steam system. Is it possible to shorten a supply riser? The current riser comes out of the floor and I would not have access to any pipe connection below the floor (multi unit building, with apartment below), and would love to avoid cutting into the hardwood floor. I also don’t want to avoid meddling with pipes below because they are very old. If I cut the riser above the floor, I would be cutting the threads. I’m taking into account EDR. Any suggestions?

Comments

  • JUGHNE
    JUGHNE Member Posts: 11,627

    Pictures would be good. Is the inlet up high on the rad or down low.

  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 20,864

    No reason you cannot cut the riser and rethread it.

    Mad Dog_2
  • Mad Dog_2
    Mad Dog_2 Member Posts: 8,719

    I know what you're trying to do. Everything hinges on the depth of the threading stock. Mad Dog

    Consulting by Mad Dog & Matt Jr.
    RadiatorFan
  • RadiatorFan
    RadiatorFan Member Posts: 13

    Thanks. I think I understand about the stock length/depth of the threading tool. Pipe is far too close to the wall for it to rotate much, so re-threading may not be an option. Any other suggestions on how to shorten the riser without removing it from the below floor pipe? Both rad inlets are up high.

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  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 20,864

    Looks pretty tight. If you disconnect it from the rad and move the rad out of the way you may be able to pull the pipe away from the wall and shove a wood block behind it to hold it off the wall enough to get a threader on it. If you can't you can't. The more you have to shorten it the tougher it will be. Maybe replace the rad with a different type a wall mount rad you could mount higher and use the existing thread. You won't know how much the pipe will move unless you try. Some risk with old pipe.

  • RadiatorFan
    RadiatorFan Member Posts: 13

    Thanks all - appreciate the suggestions.

  • RadiatorFan
    RadiatorFan Member Posts: 13

    Well, I'm still looking for a solution to changing out an oversized radiator to a smaller, shorter one. Oversized rad was 38" and replacement (from another part of the house) is 20", so the steam riser is eight inches too tall for the replacement. I want to use the 20" rad if I can.

    Disconnected the oversized radiator, and the steam riser pipe is about 1.5 inches from the wall, with some give, so it could extend about 2-2.5 inches from the wall. Because the riser is so close to the wall, I'm not sure cutting and rethreading the pipe is doable (and probably risky because pipes are 90 year old.

    Instead, can I add some sort of elbow add pipe to the riser, so that it loops down to the 20" rad? Would that change the way the steam gets to the rad in any way that is negative?

    I have about 4 inches of space to work with, so the loop would have to be tight. Thanks for any suggestions.

    (I'm taking account how much heat I need and the smaller rad works.)

  • JUGHNE
    JUGHNE Member Posts: 11,627

    Show us the other end of the rad.

  • mattmia2
    mattmia2 Member Posts: 17,921

    if this is 2 pipe why nor just put an orifice plate in the union to the larger radiator to limit how much steam can get in to the radiator or throttle it with the valve?

    JUGHNE
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 20,864

    No you can't loop down unless it is 2 pipe. If you have 1 1/2" between the edge of the pipe and the wall you should have enough room to thread it.

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