I have a 1900 three floor, 4800 sq Foot home in Detroit. One pipe parallel flow steam heat, with a 10 year old 240K Burnham gas boiler and 22 radiators of all sizes.Thanks to this site and the Holohan books, I have tamed the beast to a mostly quiet and efficient heating system.
I have two noisy spots I can't figure out. Worst, a riser from the second to the third floor hammers moderately when the steam comes up, a problem because the pipe is right behind my bed headboard. A second one is a radiator that hammers badly at the far end of a branch run on the first floor, it is the only unit on that branch.
I have insulated the mains, and have Gorton #2s at the end on all the long mains, and new vents on all of the now properly pitched radiators. The pressuretrol is adjusted about as low as it can go. Attached a drawing with pipe lengths of the basement Layout and vent locations, and where the offending items are located on the floors above. I also attached a photo of the boiler and piping.
I really don't want to tear open the plaster wall where the riser is, and really cant figure out why that would make noise when all of the nearby radiators are quiet.
Reading over again the books and the comments here, do I need to add main vents vents to these branch lines that serve the noisy members? Or is there something else I need to be looking for.
Advice is appreciated. Thanks.