Banging Steam Supply Pipe

Viggen1

I have a two pipe steam system and every radiator is working fine except the one in the upstairs guest room. It is the second shoot off the furnace. The supply pipe will bang in the floor right below where the pipe comes out of the floor to get to the radiator. The pipe will get warm/hot about 4 inches above the floorboards but steam won't enter the radiator. I took off the return coupler to try and bleed the air through the radiator but that did not work. I also checked the steam valve to make sure it was open and that was working fine too. Any suggestions on how I can get this radiator functioning? Thanks

Jamie Hall

You are brave to take the return coupler off with the boiler running. If that had been the problem, you wouldn't have gotten air -- you'd have gotten steam and be badly burned by now.

A pipe banging almost always indicates water trapped in the pipe. Question is why and where. Look for any horizontal, or near horizontal, lengths of pipe which don't pitch so that the water can drain back to the boiler in one direction or the other. First place I would be suspicious of would be that location in the floor which you mention.

Viggen1

It has to be right under the floor where the steam supply comes up....is there anything I can do to get the water out without taking up the floor?

Ironman

If the piping will allow, you MAY be able to get the sag out of the piping by raising the radiator and shimming it with some blocks of wood. Sometimes, 3/4" can make a difference.

KC_Jones

Viggen1 said:

It has to be right under the floor where the steam supply comes up....is there anything I can do to get the water out without taking up the floor?

You aren't trying to get the water out, you need to prevent the water accumulation. The water accumulates due to improper pipe pitch.