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venting the main with how many BigMouth vents ??

I wish to vent a non vented main to speed up the steam to the end. I timed it closed with no vent and it took 8 minutes 40 sec. Then removed a capped 3/4 opening and timed it at 5 minutes 40 sec. Since it buys 3 minutes my question is how many vents are needed to accomplish this using barnes bigmouth 3/4 . would it be 3 vents ? 3.2 cfm each . ??
Maine Vent


  • Jamie Hall
    Jamie Hall Member Posts: 23,654
    One big mouth should be ample.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    STEAM DOCTOR Member Posts: 2,041
    Personally, I wouldn't use and BM's. Once upon a time, I was a big proponent. They are great when they don't leak. Unfortunately, I had way too many callbacks. Including some instances of property damage. From leaking steam, not water. This after several redesigns. Including some that were tested and not leaking at time of installation. No more.