Capped radiator pipe not drawing heat?

Chicago5499

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. 

Fred

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.

STEVEusaPA

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.

Chicago5499

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

STEVEusaPA said:

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

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.

Chicago5499

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

Chicago5499 said:

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?

Jamie Hall

Chicago5499 said:

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.

Fred

Chicago5499 said:

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

I would not trust the same contractor who did not cap the pipe.