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"3 cracked radiator vents"

main vents for steam heat

These cracked radiator vents, labelled “USAV 880B,” were masking an even greater problem in the crawl space — no real air elimination vents on the mains.  The one that was located on the southern main, turned out to be an old Hoffman #43, a convector air valve, not a mains one.  Who knows how well it vented air.  Besides, it was covered with rust.  It needed to be replaced.

"old main???"

"hoffman air valve"

First I replaced it with a Gorton #1, since G2’s are better ordered online than bought locally, at least in New York City. The G1 was not enough. Calculations showed that eliminating the cold air in that main steam pipe from the boiler within 1 minute required a venting capacity of about 1.3 cfm.  While the G1 eliminates 0.33 cfm, the G2 is rated at 1.1 cfm.  I bought fittings to match the ‘antler’ pipe to the 1/2″ male of the G2.  In order to fit it in the space I had to play with the angles, as you can see below.  For more information on steam heat, is an indispensable resource.  Some very knowledgeable professionals post regularly on the forums there.

"G2 installed"

3 Responses to main vents for steam heat

  1. Pingback: alternatasha » Archive » home heating index

  2. David Fay says:

    Way to go Natasha. Not many people can hack a steam system these days.


    • admin says:

      Thanks, David! Actually it was a fun little project — the hardest part was physically unscrewing the vent from the antler! I managed to get it off only with the nipple connected, so I took the entire group of pieces to the local hardware store thinking I could get the exact same nipple and start from the bottom new. They didn’t have it, so I had them unscrew it for me. It took two guys and three different pipe wrenches until it came apart. 😀

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