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crash2009 Member Posts: 1,484
I am planning to double vent a couple radiators.  I have talked to a couple people around here and they all tell me to go to a machine shop and have the radiators tapped.  I have had a close look at the radiators that I want to do and they seem to have a plug.  Can you have a look at the pictures and tell me what this circular thing is on my radiator?  What is it likely made of?  Can I just drill through it and tap the hole.  Does it need to be removed and the tapping cleaned out? Or, How do you tap a radiator with what I have to work with? 

I realise that I will not be tapping the inlet valve side.  The other side has a vent at the top and what appears to be a plug like the one in the picture.


  • Gordo
    Gordo Member Posts: 764

    Just wondering why you need to add another vent to this small radiator?  Do you have properly sized steam main vents?
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  • crash2009
    crash2009 Member Posts: 1,484
    This one

    is not the one I want to tap.  How do you tap a radiator for a second vent?
  • Polycarp
    Polycarp Member Posts: 135

    I'd echo Gordo.  That's a pretty small radiator to be double-venting considering the basic principle of "vent the mains fast and the radiators slow."  Are your mains sufficiently vented?  Is this an especially long riser?  If either of these are the problems, then these are where your solutions should be.  Over-venting a radiator in order to vent a main or riser is really a last resort.
  • crash2009
    crash2009 Member Posts: 1,484
    How about

    this one then.  It is a 3 column 9" X 38" with 11 sections, EDR 66, most of the time it heats only 3 of 11.  It is part of a 72 LF, 2.5" main.  Main has 2 vents on an antler, Hoffman 75 and Gorton 1. 
  • Steamhead
    Steamhead Member Posts: 14,831
    You need more main venting

    start with two Gorton #2 vents on the end of that main. Then the steam will reach the radiator more quickly.

    If you put too much venting on the radiator, it can cause banging in the runout and riser.
    All Steamed Up, Inc.
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
  • crash2009
    crash2009 Member Posts: 1,484
    I had

    a G2, G1, and a H75 on this main before.  I got too much noise in the near boiler piping.  I had to remove the G2 to quiet the system.  The boiler was piped incorrectly, it needs to be redone. 

    I just wanted to know how to tap a radiator? 
  • Patrick_North
    Patrick_North Member Posts: 249
    Couple of things-

    First off, I'm not a pro.

    Using two vent tappings is not done JUST to increase venting- that much can be accomplished simply by using a vent with more venting capacity. Using two radiator vents can be helpful on very large radiators because it helps to expel air from the radiator in a more even, controlled manner- helping to ensure that it heats fully but not too quickly (which could lead to water hammer). The radiator in question (second picture) doesn't seem that big. Why not try a vent with greater capacity, first? What kind of vent are you using? Is it in good working order?

    You may alleviate some of your problem with a modest increase in venting to this radiator (and thereby altering the balance among the radiators served by this main), but a substantial increase may just bring back the water hammer you sought to eliminate by removing main vents.

    That said, yes, you can add a second vent tapping to a radiator yourself. "The Lost Art of Steam Heating" has a nice aside on just this topic. This book may help you decide if it's appropriate in your case and gives details on how to do it properly. If you've used a tap before, it's not particularly difficult.

    It seems that bullhead T in your header is the real problem. I'd bet that addressing this will tender much greater rewards.

    Good luck!

  • Charlie from wmass
    Charlie from wmass Member Posts: 4,195
    Crash to answer your question

    Yes that is where one drills and taps for a vent but it will not help due to two reasons. 1- the boiler piping is wrong, you know that so no point in belaboring that point. 2- it is on the same side as the inlet. Soon as steam gets to the radiator it will close off before it crosses the radiator. This will allow "nice" wet condensate laden steam rush to the radiator then you will have other issues. Save your time and energy and save up for a repipe. No point in risking cracking that nice radiator to make your situation worse.
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  • crash2009
    crash2009 Member Posts: 1,484
    Thanks for all the answers and opinions guys

    I understand now that it is indeed a risky and possibly unnescesary action to 2nd vent a radiator.  It appears that correcting the near boiler piping and venting the mains properly, should be done first.  That little radiator at the top of the page has been very difficult to heat.  The steam has been bypassing it most of the time for 30 years, according to the previous mgnt.  I installed a Gorton D on it and got it working on a regular basis now.  Yes, I am venting the riser through the radiator.  So, I thought if .540 "GD" got it working regularly maybe 1.080, 2  GD's might be better.  But you are right in that it would end up to be a waste of time after I eventually re-do the near boiler piping. 
  • Rich Baker
    Rich Baker Member Posts: 12
    Use an antler

    Just make a small antler.  No need to tap.
This discussion has been closed.