Dead Man Alert

tombig

1906 house converted from gravity. 6000 sf, coachhouse still has the carraige turntable. One pipe hot water (original owner was an eng.) 5" supply to attic, downfeeding from there. I have no idea how the upper floor radiators are "one piped" off the return risers droppers?). There is seven of them in the basement. All I can see is basement piping. At the bottom of each riser and at each 1st. fl. rad. supply is 1/2 drips connected to each other back to the boiler room. The pipe is teed to 3-6 risers/rads and stays 1/2" to boiler room. I'm attatching a sketch. A survey from 19?? says these are drains to drain the risers for service after closing a valve in the attic. Since the pipe is capped near the boiler rather than near a drain I think this was an integral part of the original gravity designed system. I'm thinking of connecting this to the return side of the boiler to assist in gravity flow throgh the 1st. floor radiators. Create a pressure differential to pull hot water from the single pipe distribution and let gravity do the rest? They really are heating fine but Father Larry has a cold chapel in the basement and that's another story.