Clarification on venting and mains

info43

I read somewhere on this board that mains should be vented quickly and radiators slowly. When the pros say mains, does apply only to the pipes feeding off the header along the basement ceiling or does it include the pipes that go up through each of the floors to feed the radiators as well?

The enclosed picture shows the piping I am questions, show they be vented quickly also or not at all?
Thank you

New England SteamWorks

Well, if you are in NYC and those risers go up a whole bunch of floors, then yes, ideally they should be vented at the top. But if they are just going up a floor or two to an individual radiator, then vent in the basement.

info43

Thanks for the reply. Yes, this is in NYC. I have 11 in total. 2 of them go the top of the third floor, those don’t feed any radiators but they do have a vent near the 3rd floor ceiling. The other 9 go though the 1st and 2nd floor, I don’t see the pipe on the third floor. Each pipe appears to feed one radiator on each of the 3 floors.

Paul Fredricks_3

If they only feed one radiator then you don't need a main vent, but it it is a long run you may have to have those radiators vent a little faster just to keep the heat even.

info43

Thank you both for the reply. It is appreciated.