Banging supply pipe in 2-pipe steam system

Rachel-m

Hello everyone. I've read a lot of discussions on this board and found it very helpful - but still seeking some advice on my problem. My husband and I bought a unit in a coop in DC that was build in 1906. It is heated by 2-pipe steam radiators where the supply line and condensate line are both on the bottom. We moved in late August. On October 15 the heat was turned on we now get a morning wake up call of banging and clanging.

An email to the whole building revealed that the neighbor below is having the same problem, but no one else in our stack is complaining and the neighbor 2 floors above says no noise. We have multiple radiators but only the one in our bedroom is making noise. We had a plumber come and look, he opened up the steam trap and said it was in good condition. He suggested that the problem would go away once it is consistently cold.

While the banging is happening if you touch the radiator it is not vibrating. The banging seems to be coming from the steam supply pipe. We shimmed the radiator which seemed to help a bit but still get the daily banging chorus.

Does this sound like something that could only be fixed by looked at the supply pipe (necessitating excavation into the floor, wall and who knows what else). The previous owner said she doesn't recall anything like what we are describing. I know here have been leaks and banging in the building in the past but have yet to find out how they were resolved.

Many thanks for your thoughts!

BobC

There could be water trapped in any horizontal pipe, if the radiator already had a little slope towards the return it might be worth raising the whole radiator by 1/4 or 1/2" - just make sure it's dome gently!

Bob

Rachel-m

Hi bob do you mean put shims under all of the radiator feet, and keep the slope towards the return line? Thanks for your help.

BobC

Yes, raising the whole radiator might make a difference but please do it gently.

Bob