Noises only from one radiator

C. Price

I have second floor radiator / pipe that is making water hammer noises when the heat first kicks on, none while the system is working and a few noises right after it shuts off. I've replaced the air valve on the radiator. No change. It does spit and hiss, though.
The pipe leading up to the second floor is exposed to the room, but there are two other pipes like this in the house that don't make any sounds. There is a two foot section of pipe exposed in the basement as well, but the rest is insulated. What else could be making these noises. All the other radiators heat fine with no noise.
Any suggestions on what is causing the noises ?
Thanks,
Chris in Central Jersey

GusHerb

steam

go to this page of the site it mite help. http://www.heatinghelp.com/steam_problems.cfm

Ron Schroeder

Chris

check for pitch on the pipe, a cncentric reducing coupling in the line that holding back condensate or bad trap if its a two pipe system