system includes a 30' extension on loop2 truncated w/ a #75 vent. Aiming for a 4 minute vent of mains, An 8-10 minute closure on all 9 radiators after 178000 BTU nat gas firing of a PB 63-64 boiler... size 04.. @ 1 oz. pressure. System has 500 sq. ft [EDT] of cast-iron 3-column radiators. Once clean, intend to install 9 hoffman 1A vents, and adjust. See enclosed spreadsheet [.xls file] showing details that lead to hopefully 8 minute closures of all 9 vents. What do you think? Anything amiss here? Currently in need of balancing, as rooms vary in temp. and vents are widely intermittent in the 3-story 4-bedroom 1900's house. It's working but its likely inefficient, as it whistles, hisses, and sometimes allows a room to cool, or overheat. Burners are clean, blue to yellowtips, and water usage is up due to vents allowing steam to sometimes pass for minutes at a time... Furnace, pipes, radiators all in nice shape. Vents painted, and in immediate need of replacement. Sight glass too high, cloudy, but not muddy. Ready for a good cleaning. This week!
Thanks for looking. Critiquing comments welcome. Encouragement appreciated. Engineer type, tool guy, not new to plumbing, hvac, vehicles, furnaces, forced air or hot water, elec, gas, coal, wood, or oil, but kinda new to single-pipe steam.