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Installing steam air vent

bob young
bob young Member Posts: 2,177
best method is weld a boss [threadolet ] on main .


  • Sizzlaw
    Sizzlaw Member Posts: 11
    Drilling and tapping into steam pipe

    I need to install a 3/4 inch pipe (for an air vent) near the end of the 2-inch main pipe. This main appears to be very hard to drill and tap into. Is there a best way to do this? Please e-mail suggestions to [email protected]
  • Al Letellier_18
    Al Letellier_18 Member Posts: 7
    new vent

    .......or cut the main and thread in a new tee. No easy way. Drilling and tapping a 3/4" pipe into a 2" main IS NOT an option any pro would consider doing.
  • Steamhead (in transit)
    Steamhead (in transit) Member Posts: 6,688
    Do you need 3/4-inch?

    How much air do you need to vent? How long is the main, and is it all 2-inch pipe?

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  • Sizzlaw
    Sizzlaw Member Posts: 11

    The main is about 25 ft long with several tees for branches to radiators along the way. The existing main vent is probably 30+ years old, will not close, and is on a 1/8 inch nipple on the elbow (at the end of the main) that directs the condensate downward. I have been told that the vent should not be on the elbow but should be about 15 inches back from it and that a high capacity vent on a 3/4 inch nipple would result in faster heating of the radiators, which I would welcome.
  • Sizzlaw
    Sizzlaw Member Posts: 11

    I believe the main is all 2 inch pipe.
  • Dale
    Dale Member Posts: 1,317
    Cut and weld

    Shoot a small hole with a torch and then weld on a threadolet or a extra heavy 3/4 inch coupling which may be easier to find. Leave a loose 3/4 in cast iron plug in while you weld. This sounds like a big deal but with the little portable torches and 120Volt welders I could do this in about 1/2 hour if I walked in with clean steel and access on the top of the pipe. In an old house this is definately a 2 person fire watch job, clean up everything before you start and wet down near wood. Then have a water hose ready to go. One unnoticed spark in an old basement can ruin your day.
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