so this is a system that i have moved onto 'vapor' pressure, i.e. under a pound although it never tripped the old steam limit so it may have been vapor all along, with 6 mains to 6 apartments. single pipe but the mains are parallel flow each full circuit return to boiler and because the old snow man was replace with a nice low burnham atmospheric I have over the 28" A/B difference to do away with the condensate pump.
Presently the returns are all 2" except one that is 1.5". that all discharge into 1" [email protected]
Trap and 1" lines to the condensate tank. I don't have the actual figures for radiation on each leg although i thought of maybe opening the union under one of the traps and just measuring the condensate in an hour of firing at design temp kinda thing would give me a rough idea of how much condensate i'm trying to move by gravity. But is there a rule of thumb, if you had one main at 2" like 1 or 1 and 1/4" wet return?
And maybe if i can translate that condensation into steam I can figure how large an air vent I ought to be adding at the end of the dry return.
After reading the threads on propress and steam returns (unless there has been a change), i'm thinking i'm going to sweat this stuff 95/5. The equalizer on this job is already copper so easy join. the combined return for all legs I'm going right up the equalizer size of 2". the wet return manifold will have 4 elbows. and about 8 feet of pipe.
Any other thoughts, cautions, etc. appreciated.