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Steam main venting

I just bought a 1940 house that has an oil boiler / steam radiator heating system.  There are eight radiators in the house: six on the first level and two upstairs in the finished attic.  The upstairs does not heat very well and the air vent on one of the two upstairs radiators hisses extremely loudly.  I have noticed that it seems to take a relatively long time for all of the radiators in the house to heat up. 

After reading through some of the posts on this site, it sounds like the first thing to check is venting of the steam main. 

The steam main is a 2 inch diameter pipe with two legs going in opposite directions from the boiler. The first leg is 32 feet long and it has a Gordon No. 1 air valve at the end farthest from the boiler.  The other leg is 48 feet long and it has a Dole No. 1933 (3/4") at the end.

Does the steam main seem properly vented?  (I believe it probably is not).  Can someone help me with a recommendation?  Thanks for your help!


  • RazrBlazr
    RazrBlazr Member Posts: 3
    Additional information

    Here is some additional information, in case it is pertinent:  Each leg of the steam main feeds four radiators. The shorter leg (32 feet) with the Gorton No. 1 vent feeds four radiators all on the first level.  The longer leg (48 feet) with the Dole No. 1933 vent feeds two radiators on the first level plus the two upstairs radiators.  The upstairs radiator that hisses loudly is on this longer leg and is the one closest to the boiler.
  • nicholas bonham-carter
    nicholas bonham-carter Member Posts: 8,575
    venting trouble

    i think your diagnosis is correct-at least one of your vents is not functioning properly. in addition, you should check the pressure of your system, and keep it at 1 PSI or less. the hissing could indicate too much pressure. 

    when you order another vent, such as a gorton #2 [my favorite!], you may want to order two of them at the same time, to save on postage. as you can never be over vented, you are not wasting money, by buying more than you need. you will immediately notice a difference, when you have replaced them both. for the longer main use an antler, and keep the old gorton on that one [if you can blow through it].--nbc
  • RazrBlazr
    RazrBlazr Member Posts: 3
    Balancing the two mains

    Thanks for your help! 

    I am ready to order a couple of Gorton main vents, but I want to make sure I get the right ones.  Should I be concerned about balancing the venting capacity between the two mains or is that not important?  The longer main feeds the two upstairs radiators and I'd like to try to get those to fill just as quickly as the radiators fed from the shorter main.  The two options I am considering are:

    Option #1:  Use two Gorton #1 vents on the 32 foot main, and one Gorton #2 vent on the longer 48 foot main.  For this I'd reuse the Gorton #1 vent I already have, and order a Gorton #1 and #2.  A little cheaper and possibly more balanced?  i.e., will this help both mains fill up at the same time?

    Option #2:  Use a Gorton #2 vent on the 32 foot main, and a Gorton #2 vent plus a Gorton #1 vent on the longer 48 foot main.  For this I'd order two Gorton #2 vents and move my existing Gorton #1 to the longer main.  More venting capacity but a little more expensive and potentially less balanced between the mains? 

    Which of these would be better for my setup?  I do realize the Gorton #2 is significantly larger than the Gorton #1.  Also, either way I will need to install an antler for both mains because the vents are currently screwed directly into the return elbow.  I have about 15 inches clearance between the top of the elbow and the ceiling boards above, so I think I have room.
  • Vents

    You don't seem to have clearance problems so  I'd just use a Gorton # 2 on both mains. Since you're using an "antler" anyway using the extra  Gorton # 1 on the longer main makes sense. . The object is to get the steam to the radiators as quickly as possible which means getting the air out of the way as quickly as possible. Balancing  the mains really isn't a concern.  With the mains there isn't a thing as "over venting"  You can have "excess venting" but that's an economic thing and doesn't affect the operation of the system.

    The radiators are a different story and you want to try to balance them for quick even heat through out the system. You have to be cautious though because if you try to vent a radiator too quickly you may have problems with the large volume of outgoing condensate colliding  with the incoming steam.  Be sure to use a pipe union to attach the antler as that makes installation / servicing much easier.

    - Rod
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