| Application: | Main Vent |
|---|---|
| System Type: | Steam |
| Size: | 1/2" |
| Model: | Gorton No. 2 |
| Mount: | Straight |
| Adjustability: | Non-Adjustable |
| Material: | Steel |
| Body Pattern: | Straight |
| Thread Type: | Male |
| Temperature Range (F): | 140°F - 240°F |
| Thread Size: | 1/2" |
Please refer to the link below. http://s3.pexsupply.com/manuals/1285962872991/39827_PROD_FILE.pdf
In Dan Holohan's book "Greening Steam" is a chart of venting capacities of various different air vents. Gordon #2 comes in at 2.2 CF of air venting capacity per minute, at 3oz of pressure. This vent is mounted on a 1/2 inch MPT. An open 1/2 inch pipe allows 4.8 CF of air flow per minute at 3oz of pressure. If your main vent tee is 1/2 inch or larger, you can, theoretically make up a pipe branch and attach 2+ of these babies to get it venting at pretty much a rate of open pipe until the steam hits it. This is where you want to be careful if there are several loops (zones). You want all of them to vent evenly, thus make sure whatever you do, it's the same on all sides. Then, the risers should, in theory, all start filling with steam evenly, at the rate radiator vents will let them. I highly recommend the book "Greening Steam". You will learn a lot about your system and will probably just from it know more about steam systems than 95% of 'contractors'.
I agree with Mickey D, except if your branches are different lengths (differing amounts of trapped air) you may need different venting on different branches to have all radiators get steam at the same time. The longest branch (most distant main) needs the most venting.