Best Of

Thanks for the comments and help - been reading Lost Art of Steam Heating (revisited) and learned more about my system in past week than knew in 18yrs i owned this place. my service has been done by oil company guys. Up until couple years ago i had hot water from boiler (now separate gas hot water) and there was 2nd zone with 1/2in copper feeding baseboards in basement fed by pump that burned out. I had that all removed. There were old Hoffman non-adjustable vents on radiators for 1st and 2nd floor (4 radiators 2nd floor and 6 on1st floor) with 2 mains feeding front of house and back. Had and still have uneven heating and a couple slow radiators (2 biggest)- oil guy took all old vents off put on cheap home depot vents that shrieked like steam kettle and blew steam. Replaced them with new adjustable Hoffman vents. Got guy not associated with oil company to do clean service of boiler last few years. Used to have bad water hammer when did hot water from boiler- now know water level was too high- old glass was marked > 7/8 full by one of oil co service guys years ago saying i needed more water in boiler for hot water. Far less water hammer now system still not balanced but works better with less water in boiler (1/2 full).
My 2nd question is can someone please identify that horizontal copper pipe off copper leading to header? Please see photo.
My 3rd question is the main vents. Any idea make model? Home was built 1950 any chance these are original vents? I see they are on elbow. there's space to put one back and up but other has beam in way- can i have 45 degree riser used to get by beam and put new vent on top of that?