Very interesting problem

ChrisJ

I think I figured it out but wanted to share the experience.  Back in April we bought our house which had some issues with the heat.  Besides the rotted boiler which I didn't find out until later,  it had a steam pipe with a hole in it under the downstairs bathroom.



Well, asked the seller to fix it and they didn't so after we lived there two nights they finally had a plumber come and replace the pipe.  After he replaced it the radiator in that bathroom didn't get hot.  I didn't think anything of it as I only ran the heat once and I had two other rads that didn't get hot due to an undersized boiler.  



Well, with the new boiler installed which is plenty for the system its still not getting hot!  This morning after the system raised the temperature over 10 degrees in the house that rad was still ice cold.  I decided to close one of two king valves to raise the pressure as it was still at or near zero.  The pressure began to climb and around .5PSI  I got "woosh, woosh BANG!! bloop BANG!!" from the pipe going to the radiator which wasn't working.  It took me an hour of thinking but I finally realized,  the seller's plumber broke it!  He took the drain out!!  (The hole).

In reality,  the pipe is obviously pitched the wrong way due to the house settling and honestly, I wonder if someone drilled the hole in the pipe to fix this problem.  It was around 1/8" in diameter.  I'll either be raising the radiator, or replacing swapping out the nipple that runs down through the floor.