Morse Code

Paulvar1

I replaced my steam boiler in December. It has been flushed twice and there is no longer any banging. However my bedroom radiator has started ticking like someone GENTLY tapping Morse code with the tip of a screw driver. It is not loud, but is enough to wake me in the middle of the night when the heat turns on. It has never done that before (30 years). It is short lived, presumably, when the radiator fills with steam, it stops. The radiator has a proper pitch and the supply and return pipes are a vertical drop so pitch isn't an issue. (Please no poltergeist jokes). The system is 2 pipe open steam. Feed on the bottom of one side is 1 1/2" end return on the bottom of the other side is 1 1/8" (measured with a caliper) that returns to the wet loop in the basement. My pressure is about 1.5 lbs . Everything functions reasonably well and the heat in all 11 rooms is great. The disturbance of my sleep is maddening. I changed the steam vent just to increase the speed at which the radiator heats to stop the infernal tic tic tic faster. It still tics the same amount of time.

EBEBRATT-Ed

Or maybe when they installed the boiler the pipes moved slightly.

Try cutting some plastic (like a bleach bottle) cut some small pieces and put it under the legs of the radiator. Check to see if the supply and return pipes are rubbing on the wood.

And try slowing down the venting on that radiator