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Twp pipe radiator with an air vent?

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georgearoush
georgearoush Member Posts: 27
in Strictly Steam

I have been reading "We Got Steam Heat!" and noticed that the book covers traditional two-pipe radiators, but it doesn’t address the type I have.

In the book, two-pipe radiators are described as having no air vent, but my two-pipe radiator does have an air vent, and its configuration is quite different from the example shown. Here’s how:

  1. In the book, the supply valve is located near the top of the radiator.
    On my system, the supply valve is located at the bottom of the radiator.
  2. The return valve on my radiator is at the bottom on the opposite end, which matches the book.
  3. Additionally, my radiator has an air vent at the top of the return side, something the book’s example does not show. In fact, the book states, two pipe radiator do not need an air vent!

Can someone explain why my radiator’s design differs from the one described in the book, and why the book might not cover this type? Also, in my case, should the air vent be closed? If not, should I size and adjust the vent opening the same way the book recommends for one-pipe radiators?

Comments

  • NewGuy
    NewGuy Member Posts: 29
    edited December 8

    I have the same setup on just one out of 18 radiators in our building. The other 17 are one pipe system, only this one is two pipe. And when the valve is shut, the air vent spits water that I assume is pushed back up from further down the return line (because we removed a cap at the beginning of the return and it spit there, too). I don't have any answers for you except to say that two pipe systems do have vents, but they are usually somewhere else in the steam lines. I think people sometimes add the air vent to the radiator, for better flow, instead of doing the slightly harder job of cutting into a pipe somewhere else and adding one. We have since taken off the vent and plugged the radiator, but now the steam flow is weaker/less consistent. I'm curious to hear what more knowledgeable folks have to say on this.

  • 109A_5
    109A_5 Member Posts: 3,400

    Don't be too ambitious to change things until you know the system well. There are two pipe systems with air vents on the radiators but they are a lot less common.

    What actual issues does your system have heating the house ?

    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
  • mattmia2
    mattmia2 Member Posts: 15,517

    can you show a picture of a radiator and the boiler? are you sure it is steam and not hot water?

    steam air vents should be about 1/3 from the bottom of the radiator.

    hot water bleeders are at the top of the radiator

    sometimes people add air vents to 2 pipe systems in a misguided attempt to fix other problems.

    the lost art of steam heating covers 2 pipe air vent systems but they aren't very common and generally predate air vents and steam traps so they might not be covered in we got steam heat.

  • cd1
    cd1 Member Posts: 13
    edited December 8

    I asked a very similar question a few days ago and received some very helpful responses. See link below.

    https://forum.heatinghelp.com/discussion/202831/what-type-of-steam-system-do-i-have

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