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Capped radiator pipe not drawing heat?

We are having our kitchen renovated in our condo and one of the construction workers made a BIG mistake. A radiator pipe that was sticking up above the floor (with no radiator attached) was meant to be cut below the level of the floor, capped, and new flooring laid over it as we didn’t need the radiator in our small kitchen. One of the guys did not cap it, laid flooring over it, and the first time our radiators kicked on since we’ve moved in steam was released through the floors and up in to the walls causing some damage to hardwood floors and our downstairs neighbor’s ceiling. When we realized the pipe wasn’t capped, the flooring was pulled up and it was capped correctly. To test the cap, the building engineer turned the boiler on to manual so that all the radiators kicked on in the building. The mystery of this story is that the radiator pipe we thought caused all the damage did not get hot or even warm to the touch. Is there any scenario where once a single radiator pipe is capped it doesn’t still draw heat? We are now afraid that there is another pipe somewhere that is causing the problem. 

Comments

  • Fred
    Fred Member Posts: 8,542
    That is normal. Once a steam pipe is capped, it holds air in it that can't escape and the pipe will remain cool/cold to the touch.
    Chicago5499
  • STEVEusaPA
    STEVEusaPA Member Posts: 6,506
    edited September 2020
    Steam won’t reach the end of that pipe if the air can’t get out. So it won’t get very hot, if capped correctly.
    If there was another pipe not capped, wouldn’t you see steam?
    If the steam boiler was running, and steaming, and all the radiators were getting hot, and no leaks, you should be good.
    steve
    Chicago5499
  • Chicago5499
    Chicago5499 Member Posts: 4
    Fred said:
    That is normal. Once a steam pipe is capped, it holds air in it that can't escape and the pipe will remain cool/cold to the touch.
    That’s what I was thinking but our contractor disagreed. He expected it to still get hot and since he obviously has more experience than us it has made us nervous that we didn’t resolve the issue fully and will flood our neighbor’s condo with steam again. 
  • Chicago5499
    Chicago5499 Member Posts: 4
    Steam won’t reach the end of that pipe if the air can’t get out. So it won’t get very hot, if capped correctly. If there was another pipe not capped, wouldn’t you see steam? If the steam boiler was running, and steaming, and all the radiators were getting hot, and no leaks, you should be good.
    That’s a good point. The concern is that it didn’t get hot at all. The pipe and cap remained cold to the touch. 
  • Fred
    Fred Member Posts: 8,542
    He is wrong. If the air can't get out, the steam can't get in. If a radiator were on that line, it would have a vent on the radiator to let the air escape from both the feed line and the radiator.
    mattmia2Chicago5499STEAM DOCTOR
  • Chicago5499
    Chicago5499 Member Posts: 4
    Fred said:
    He is wrong. If the air can't get out, the steam can't get in. If a radiator were on that line, it would have a vent on the radiator to let the air escape from both the feed line and the radiator.
    Thanks for your expertise Fred. Any opinion on the chances of mold within the walls from steam being released? As far as we can tell, the area around the hole that was opened in the floor is dry and looks fine but our downstairs neighbor is still concerned. 
  • pecmsg
    pecmsg Member Posts: 4,843
    edited September 2020
    Fred said:
    That is normal. Once a steam pipe is capped, it holds air in it that can't escape and the pipe will remain cool/cold to the touch.
    That’s what I was thinking but our contractor disagreed. He expected it to still get hot and since he obviously has more experience than us it has made us nervous that we didn’t resolve the issue fully and will flood our neighbor’s condo with steam again. 
    Then he shouldn’t be working on Steam?
    Chicago5499STEAM DOCTORmattmia2
  • Jamie Hall
    Jamie Hall Member Posts: 23,276


    Fred said:

    He is wrong. If the air can't get out, the steam can't get in. If a radiator were on that line, it would have a vent on the radiator to let the air escape from both the feed line and the radiator.

    Thanks for your expertise Fred. Any opinion on the chances of mold within the walls from steam being released? As far as we can tell, the area around the hole that was opened in the floor is dry and looks fine but our downstairs neighbor is still concerned. 

    Now that the steam release has been stopped, unless there is another source of moisture it shouldn't be a problem.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    Chicago5499
  • Fred
    Fred Member Posts: 8,542


    Fred said:

    He is wrong. If the air can't get out, the steam can't get in. If a radiator were on that line, it would have a vent on the radiator to let the air escape from both the feed line and the radiator.

    Thanks for your expertise Fred. Any opinion on the chances of mold within the walls from steam being released? As far as we can tell, the area around the hole that was opened in the floor is dry and looks fine but our downstairs neighbor is still concerned. 

    As Jamie says, it should not be a problem.
  • unclejohn
    unclejohn Member Posts: 1,833
    I would not trust the same contractor who did not cap the pipe.