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A few months ago I did some basic improvements to my 1 pipe steam. I checked all my radiators for proper slope and shimmed where needed. I insulated the main in the basement, in the process re-doing some of the straps that hang the pipes from the joists. I added a Gorton No. 2 to the main, cleaned and adjusted the radiator vents and finally got even heat at relatively the same rate throughout the house. But I immediately noticed slightly more noise from the pipes and radiators. No pops or bangs, just a steady rushing or boiling sound as the boiler fires up and gets going - higher pitched and more noticeable than before. It sounds like noise from the boiler itself carrying through the pipes. Any ideas??