Help! With my steam radiators and violent banging

pweedith

So I own an old 2 family house with steam heat. Each unit has its' own system. Currently, my first floor is vacant and so without realizing the boiler ran out of water so the system wasn't operating. The unit was at 45 degrees so I refilled the boiler and the system locked on.

That's when pandemonium began! After waiting some time for the boiler to heat up the new water I started hearing violent bangs like I hadn't heard before. Vibrating the floor and the pipes. It was coming from multiple radiators so I couldn't pinpoint any specific source. I read that bleeding the radiators could help so I unscrewed one of the vents and cold water started spewing out, not gently either, it was shooting a couple feet out. I got a 5 gallon bucket and basically filled it twice from that one radiator, mostly with cold water but it did start to get warm/hotter on the second bucket.

I did the same with some of the other radiators and while I did get some water out of those as well it wasn't nearly the volume or intensity as the first one I bled. The first one that had all the water is also the furthest one from the boiler...if that matters.

Eventually, they did all get hot and the banging has subsided. I'm going to keep an eye on them as this just happened within the last hour.

I also used my level to check the pitch and of the 5 radiators: 2 were perfectly level, 1 had the bubble floating on the line, and 2 had a steeper pitch. But they were all pitched towards the pipe.

Any insight into what caused this and how I can fix/remedy it for the future is appreciated. Could it just be the fact that the system had gotten completely closed?

Also, the water level in the boiler didn't seem to drop even after the 12-15+ gallons that came out of the various radiators so I'm not sure if it was just sitting in them somehow.

KC_Jones

You overfilled the boiler, and then filled the radiators. Not sure how you did it, but need to figure that out.

The sight glass valve could be cogged giving false reading, this would explain why you didn't see the level drop, it's not reading the correct level.