The radiator in the bedroom makes a terrible screeching/rattling noise. I made a video so you can hear it (http://www.youtube.com/watch?v=-02gYmT1HWc). We live in an old building in Boston with a 2 pipe steam heating system. The problem started a couple of years ago when the boiler was changed. The noise has gotten worse over the years and wakes us up at night in the winter. Our building management company appears to be stumped as they have not been able to fix it.

We made sure the radiator is tilted towards the return pipe, but the noise persists. One idea we had is the noise is the "ball" in the trap rattling around. See, the return pipe gets very hot (too hot to touch) before the steam intake pipe even gets warm. Perhaps this is preventing the trap from opening and pressure builds up causing unnatural things to occur inside the trap.

Any help or guidance is greatly appreciated.