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.

To much venting

I have 2 Gorton #1 on a main run about 33' from the boiler. The other side is only 7' run from the boiler to the riser and it does not have a vent. If I had a 3rd #1 where I have the other 2 will I be allowing the steam to travel to that side of the house much faster causing the other side to now have slower movement of steam to those radiators?
Mad Dog_2


  • Mad Dog_2
    Mad Dog_2 Member Posts: 7,097
    Depends.. Charts and guides are useful tools but you won't really see the effects of change in vents until you actually do it. I have a saying: "ANY small change to a Steam system can make HUGE DIFFERENCES!"  SO go slow.  If I were you, add the main vent and then adjust radiator
    By radiator with your Gorton or Hoffman Air vents to either slow down or speed up the timing. Mad Dog 🐕 
  • SteamingatMohawk
    SteamingatMohawk Member Posts: 1,021
    When you get to the point that the venting capacity is as much as with no vents installed (open to the air), there is no advantage to adding venting capacity.

    For example if you use a 1/2" steel pipe for connecting the vents, it can pass 4.8cfm @ 3 ounces pressure. That amounts to 7 Gorton #1s at 0.7cfm or a little more than 2 Gorton #2s at 2.2cfm.

    See pages 198-199 in "The Lost Art of Steam Heating" or page 10 of the Gill/Pajek study here:


    Judge for yourself.
  • ChrisJ
    ChrisJ Member Posts: 15,767
    I have had five Gorton #1s at the end of a 32' long 2" main for a long long time now. My other main is something like 8 or 10' long =, also 2" and has a single Gorton #1.

    The size of your vents depends on a few things, the size of the boiler for example.

    If you add a vent to your longer main and cause an issue, then increase venting on the short main and keep going until you stop seeing changes.

    I highly recommend to either time how long steam takes to get from the boiler to the end of the longest main or measure backpressure at the boiler accurately (DO NOT use a 30 PSIG gauge). And do this test with all of the piping hot. Start the boiler, let it get all of the steam piping good and hot and shut it down. 5 minutes later run the test. I'm betting you'll find you need more venting.

    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment