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One pipe main vents needed?
I have a one-pipe system with mostly the original piping, which appears to have no main line(s) vents. The only venting is at the radiators. The system is not well balanced (very little steam to the two upstairs radiators on the bad side, which put out air, but never get much heat to them before the system kicks off after thermostat hits 68 degree top temp), and I am thinking that I could possibly remedy that with some venting on the side that does not get adequate heat to the radiators. My first question is...am I looking at some re-piping to add a basement vent or two, or is it possible to tap into the existing pipes? I have Dan's book and am doing some research, am hoping to find a solution. Other than poor balancing, the system works fine. Boiler is only about 10 years old. All radiator vents are working fine.