I have experience with single pipe steam heat and tuning. This new house has a mix of 2 pipe and 1 pipe radiators. All 2nd floor radiators are 2 pipes entering and exiting the rad at the floor level and all the first floor are 1 pipe and are different style except a fancy one with plate warmer that is piped with modern copper and no valves. All radiators in house ~15 have vents of various brands. In the basement, I have 3 main vents near the boiler they appear to be rusted shut that appear to loop back returning to the boiler. Underneath these 2 pipe radiators and the fancy plate warmer version are u-shaped loops that have clean outs I assume for condensate. The house has sufficient heat, most rads are only half heated and many of the vents on the rads I suspect may not be functioning properly. Personally, I am very interested in mastering this system and learning its design, proper terms, and where and why it was hacked (modernized). I had great experience with my one pipe system in my old house and accept the challenge. I have purchased (not yet arrived) "The lost art to steam heat." I spoke to Ken at Gorton who was kind enough to suggest I post here to get some advice. Meantime I purchased 2 Gorton #2's and a #1 (for a much shorter 3rd run) to replace these main vents as a first measure. I realize a 2 pipe system typically does not have vents and I do not see any small traps. I did find a large unused 2 pipe rad in the attic and I feel some of the first floor radiators had an additional hole in the floor leading me to believe the first floor may have had 2 pipes originally. I would be grateful for any education one might provide on how to begin to improve this system. Is this mixed system ok? Do I expect to start tuning the rads with regular vents?