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Vent on dry return as substitute for main vents

HarryL Member Posts: 59
My daughter's house has an oil-fired 1-pipe system in a small two story apartment. There are two mains and they run off into pretty much inaccessible points in the basement, at least in the short term. The mains are both 2" iron and about 15 feet long. Neither have vents. The returns are 1" iron. The two returns are both dry. On each return there are two vents, one is about half way back to the boiler and the second near the boiler. All four are Ventrite #35 but are stuck open. There are six radiators three on each floor. The basement is very warm - no insulation.

The short term plan is to review the radiator EDR and boiler sizing, check for water usage, repair the vent situation, and insulate as much as is accessible. (Sadly she only told me her heating bills were high recently so she's missed most of the winter, but there is next winter.)

For the vents I'd like to put Gorton #2s on the end of the mains but as I said the ends of the mains are pretty much inaccessible and will involve major work to add the taps. For now, my plan is to plug the two vents near the boiler. For the other two, replace each with a Gorton #2. The VentRites are on a vertical tee with a 3" nipple. Will having the Gorton's on the returns as I am proposing cause any problems in the returns, or damage the Gortons being too close to the return pipes?


Home owner, 1927 2-story, single family
1 pipe Burnham IN4I, Boston area


  • Jamie Hall
    Jamie Hall Member Posts: 21,512
    If the "dry returns" are actually extensions of the steam mains back to the boiler, you can put main vents on them anywhere you like and it will be fine. If, on the other hand, they are real dry returns -- separated from the steam mains by traps -- it may not work depending on how the traps are installed.

    How do you tell? Do the "dry returns" have steam in them during a run? Then they aren't true dry returns, but steam main extensions and it will work.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    EBEBRATT-Ed Member Posts: 13,759
    What @Jamie Hall said

    Just vent the returns. I like to raise the vents up as high as possible using the longest nipples I can use. The larger the vent stub the better, Reduce for the vent at the top rather than the bottom if you have a choice. If you make a vertical off sett for the vent 45s are better than 90s. Many systems were vented this way.........no issues
  • HarryL
    HarryL Member Posts: 59
    Home owner, 1927 2-story, single family
    1 pipe Burnham IN4I, Boston area