Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

Master Venting on Steam Heating Systems

HeatingHelp Administrator Posts: 634
edited January 2021 in THE MAIN WALL
imageMaster Venting on Steam Heating Systems

Frank’s “master venting” approach distributed steam throughout large buildings in a matter of minutes, with less than 1 psi steam pressure at the boiler. He learned how to do this by reading old books and magazines.

Read the full story here


  • Bob_127
    Bob_127 Member Posts: 3
    I had a large five story brownstone in Park Slope in Brooklyn that I fully renovated and restored. It was 6500 ft.² with a steam boiler. Besides venting the mains, I did what you said on the top floor of the radiators. I replaced the valves with a configuration that vented the risers and moved the valve in between those vents in the radiator. It definitely helped. However what I know now since I no longer own the house, I would’ve done a lot of air sealing and insulation too. Of course I got these ideas from your book The Lost Art of Steam which was my Bible. Thank you!
    Erin Holohan Haskell
  • westbye
    westbye Member Posts: 8
    Thank you so much for your informative and entertaining information. I have a 3 story 30 unit one pipe oil fired apt building in Springfield, Vt. The main runs the length of the building and at the end a few years ago I installed a 5 Ventright #77s and things got allot better. My question is in regard to the suggestion in the article to vent the risers (there are about 18 of them) at the top of each one. I know you don't like shortcuts but...why not just install a few Verivents (or other large vents) on the end of the top floor radiator that is nearest to the riser. Wouldn't that suffice to get the steam up there fast and when they close the rest of the radiators on that riser would fill. You have made me aware (in a different article) that the steam would be drawn only (due to the vacuume created by condensing steam) to the Varivented radiator until it was satisfied. Any info would be much appreciated.
    Your faithful reader and practicing practitioner of steam, email is: [email protected]
    Wes Cutting
  • Jamie Hall
    Jamie Hall Member Posts: 22,947
    Well... the disadvantage of using one of the radiators as a main vent for a riser is partly what you note -- it will get most of the steam until its full and, second, you lose control of the heat from that radiator.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • bburd
    bburd Member Posts: 887
    Also, venting a radiator too quickly may cause gurgling, spitting air vents and other signs that more condensate is being produced than can drain out against the incoming steam.

  • I think it may be worth a try, to max out the top rad vents, with the proviso that the intermediate radiators be vented more slowly. Using the rad vents with changeable orifices would make that much easier, than unscrewing each vent, and substituting another slower/faster one.
    I still believe that a larger capacity vent could be installed in the bonnet of the valve, after the stem has been removed, and the resulting hole tapped appropriately, although I have not had the occasion to do this myself. This however is difficult to do during the heating season.
    What is needed for simultaneous steam arrival is that the slower resistance of the radiator vents allow all the supply pipes to be filled first before steam begins to enter each of the radiators.
    On your low pressure gauge, the main venting should take place at less than 2 ounces of back pressure.—NBC