Do I have a steam main in my apartment?

superMARKet

superMARKet

Do I have a steam main in my apartment?

I live on the top floor of a 4-story walkup in Manhattan, which is heated by one-pipe steam. In one of my rooms, I have a 2" steam pipe running from the floor nearly to the ceiling. At the top is a Hoffman 45 vent on a 1/2" nipple.

There's a utility room on the other side of the wall, and it's got an identical pipe and vent.

Both the vent in my apartment and the one in the utility room hiss wildly when the system starts up. I know that radiator vents aren't supposed to hiss, and mine don't, but I'm not sure what to make of these other vents.

Are these pipes the steam mains? Or would you call them risers, but should they be vented as mains? Should there be a bigger (or different) vent than the 45 at the top?

There are no main vents in the basement, but I'm not sure I'm supposed to have any - most of the diagrams I've seen are for 1- or 2-story homes, and my 4-story walk-up obviously can't practically have all the radiators connected directly to the basement mains.

(To quote Dan:)
Thanks for all that you do for us!

Steamhead

Those risers

are being used as radiation to heat those little rooms. The vents would not hiss like that if the basement mains were properly vented.

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Boiler Guy

Question for SH

I have a 1909 4 story condo complex where all of the corridor radiation has been removed. Currently we are experiencing REAL WINTER. This AM it was -51F with a 20 mph wind it was equivalent to -59F. Tomorrow it is supposed to be colder. Your answer got me to thinking. The 1.5 & 1.25 risers are still in place. If I installed a 2' riser at each of the removed rad locations with a vent on them could I use the risers to add a little heat in the corridors?

Boiler Guy

Question for SH

I have a 1909 4 story condo complex where all of the corridor radiation has been removed. Currently we are experiencing REAL WINTER. This AM it was -51F with a 20 mph wind it was equivalent to -59F. Tomorrow it is supposed to be colder. Your answer got me to thinking. The 1.5 & 1.25 risers are still in place. If I installed a 2' riser at each of the removed rad locations with a vent on them could I use the risers to add a little heat in the corridors?

Steamhead

Yes you could

but maybe some good used radiators would work better. The original radiators using 1-1/2" risers must have been huge- you probably won't need that much capacity.

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superMARKet

You're right, those risers are smack in the middle of the building where radiators would be overkill.

But help me understand something here. If I add venting in the basement, I'd get the air out of the mains down there quickly and I'd get steam at the takeoffs sooner, but the risers I'm talking about have got to be 50 feet long. Together, those risers alone easily contain more volume than the main does between the header and where it drops into a buried return. It seems like even with main vents in the basement, there would still be a whole lot of air to push through the #45 vents.

Like I said, none of the radiators hiss, just those two risers.

Steamhead

Try

using Gorton #1 main vents on the risers. But you still need to properly vent the mains, or most of the steam will go up the risers before going to the radiators downstream of the risers.

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Boiler Guy

Add rads

Another problem is source of supply. The only place I can get any rads locally is the scrap dealer and you know how they handle stuff... anything else is weeks away. You know I just might try a couple spots .. it's not like there is going to be a big investment.