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Rusted Main Vent

Hello, everyone.

I've been replacing 2 main vents on my system. I finally got them and I replaced one of them. However, for the other, I can't seem to get the old main vent free.

The vent's threads are completed rusted. I've been trying to free it with a crescent wrench but it seems impossible. What can I do at this point?


  • nicholas bonham-carter
    nicholas bonham-carter Member Posts: 8,573
    removing recalcitrant vent

    most main vents are brass-bodied, and should come out with a few taps on the handle of the wrench, while you exert a bit of force on them. the shocks can loosen them more easily than constant force.--nbc
  • TeachMeSteam
    TeachMeSteam Member Posts: 128

    I tried tapping on it. It still won't budge.

    I also just noticed that the section of the pipe that the this vent is on, is ice cold when the boiler is on. I guess that suggests that the vent is not working.

    I googled similar situations. How about using a penetrating liquid like PB plaster?

    Hoping someone can chime in with a helpful suggestion.
  • nicholas bonham-carter
    nicholas bonham-carter Member Posts: 8,573
    pb-blaster or kroil to the rescue

    i was thinking about more than a "tap" on the wrench-more like a "whack", and yes use some sort of penetrating oil.

    don't allow yourself to get confused by mistaking the direction of rotation for unscrewing as you are probably underneath the joint." righty-tightey, lefty-loosey", when viewed from the top can get turned back to front from some angles.--nbc
  • TeachMeSteam
    TeachMeSteam Member Posts: 128

    I finally had time to get some PB blaster and it worked! I really didn't think it would. This vent looked like it's been there for 50+ years.

    I sprayed some and after 5 minutes, it still didn't work. But, I sprayed some more, waited 30 minutes, and the vent slowly moved. I almost cried in joy.
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