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Unsure about type of vent needed in 1920 house

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Hi there -

I have owned this house for only a few years. It's a two-family home.

The first floor dining room radiator vent cracked and is leaking steam, so I need to replace it. I am confused because it appears to be the size of a main vent.

I think what they did was they put the main vent here, instead of in the basement where the furnace is. I have not located any main vents in the basement for the first floor system.

Should I replace this vent with one of the same size? I think it is 1/2 or 3/4"



Thanks!

Mike

Comments

  • Jamie Hall
    Jamie Hall Member Posts: 23,295
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    That's not a main vent -- it's an ordinary radiator vent. If you can get any of the lettering off it, you could probably get the same size to save you a lot of trouble.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • lbeachmike
    lbeachmike Member Posts: 177
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    Okay - it just occurred to me as I read your response - you can tell this by the size of the little tiny vent at the top of it?
  • lbeachmike
    lbeachmike Member Posts: 177
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    Also, can you recommend what would be good to replace it with? Are you recommending that I use reducers to size down the pipe? It seems every local place sells 1/8" vents. I'm also not sure if this is safe to DIY ... it looks like it's been connected for about 100 years and I'm not convinced it's going to budge easily. I am worried about cracking something if I put a lot of force on turning it.
  • ethicalpaul
    ethicalpaul Member Posts: 5,702
    edited January 2020
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    It looks like a Jacobus #1 main vent to me. Basically the same as a Gorton #1. It may have a different orifice on it (see below).

    That said, since it has the extremely handy removable, exchangeable orifice, you can get the vent linked below and put any orifice from any other Jacobus vent onto it. Even the one from the existing vent. Look for a letter or number faintly stamped on the little orifice piece on the top.

    https://www.supplyhouse.com/Jacobus-Maid-O-Mist-J1-1-3-4-x-1-2-Main-Vent-Valve-3563000-p

    You should be able to put a decent-sized adjustable wrench on the vent and convince it to budge. I think it will move before the reducer it’s attached to does
    NJ Steam Homeowner. See my sight glass boiler videos: https://bit.ly/3sZW1el
  • lbeachmike
    lbeachmike Member Posts: 177
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    Thanks. I was just over there (I don't live there - it's rental property) - and forgot to check the model info on the part ... but I too think it's the Jocobus #1 - it was chrome underneath the dirt.

    So no difference if I reduce it down from 1/2" to 1/8" and use the 1/8" Maid-O-Mist or similar vent? No difference in venting capacity?

    I'm a little confused because Jaimie said it's not a main vent, just a regular radiator vent - but I thought the Gorton #1 or Jocobus #1 are main vents?
  • Fred
    Fred Member Posts: 8,542
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    I would say, based on what I see, it's the orifice size that would make it usable as a main vent or a radiator vent. As a radiator vent, you can reduce it down to 1/8" with no problem.
    If it was intended to serve as a convenient location for the main vent, that may pose a problem balance that radiator with others in the house. Better to make sure you have good main venting, on the main(s).
    ethicalpaul
  • lbeachmike
    lbeachmike Member Posts: 177
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    Thanks Fred. I see your point about the challenge of balancing radiator output. However, the long-term tenant I have in this apartment likes his world cool (64 degrees actually) and barely spends time there, so optimizing the heating system has been a non-issue. It seems to work reasonably well, other than doing a lot of really loud pipe clanking when it starts up.

    As mentioned in my initial post, I have no venting on the main that I can find. So I thought they probably used this location as a convenient place of a main vent. I realize that's not ideal, but my budget for property improvements has other things prioritized at the moment. And after just incurring a $900 boiler repair, I would ideally like to just replace this vent and make improvements at a later date when budget permits.

    Because I cannot get this vent off with my own tools and experience (lack of), I'm forced to have my plumber or heating guy do it tomorrow.

    All I currently have on hand are a couple of reducers and maid-o-mist 1/8" vent. Should I try to get hold of a 1/2" vent instead to match what was there? I do need this dining room radiator to work well since it is heating a larger space than any others.

    Thanks for your help.
  • ethicalpaul
    ethicalpaul Member Posts: 5,702
    edited January 2020
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    You don’t need to reduce it. The Jacobus and Gorton #1 both are threaded with a 3/4” male (used in your photo) AND a 1/2” female thread inside.

    It’s the very reasonable vent I linked above.

    But rereading your reply if you need it done tomorrow, the 1/8” is better than nothing. Tell the plumber to use tape and not crank it down too hard so you can swap it out after receiving a #1.

    I also have a rental, that is unfortunately 90 minutes away. It’s a pain in the vent
    NJ Steam Homeowner. See my sight glass boiler videos: https://bit.ly/3sZW1el
  • lbeachmike
    lbeachmike Member Posts: 177
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    Hey Paul - Yup - That's the issue - that I won't have the larger vent in hand tomorrow, and my tenant returns tomorrow night ... so I need to get this up and running tomorrow. The only 1/2" vents that seem to be locally stocked are Hoffman. Not sure if they are any good. Also not sure what the heating guy will have on his truck and at what price.

    Was planning to make sure he tapes it and doesn't crank it down too hard to swap it out if needed.

    It sounds like you're saying there would be a big difference, noticeable to the tenant, between the 1/8" vent and the 1/2" vent.

    In what way would that difference be noticed? More efficient? Less noisy?

    My rental is 0.7 miles away :smile:
    ethicalpaul
  • ethicalpaul
    ethicalpaul Member Posts: 5,702
    edited January 2020
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    There may be little to no difference in practice. Use the old orifice if you can (like if your new vent is a #4 or whatever.

    I just like to use 3/4” stuff in a 3/4” hole 😄

    My rental was .5 miles away, but then I moved :cry:
    NJ Steam Homeowner. See my sight glass boiler videos: https://bit.ly/3sZW1el
  • Jamie Hall
    Jamie Hall Member Posts: 23,295
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    Whether it's a main vent or not -- and I still say it's too small -- the location of the vent at the end of a fin tube unit will never do for main venting. If it's fast enough to serve that way, the fin tube unit will be very unhappy. If it's slow enough that the fin tube doesn't get indigestion, it won't be fast enough to do any good as a main vent.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • ethicalpaul
    ethicalpaul Member Posts: 5,702
    edited January 2020
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    It may be too small for his system, but it is a main vent, almost identical to the Gorton #1.

    I agree that it's a horrible place for a main vent, but it might still do some good in that location. I'd have to see the whole system to really know.

    I guess the question becomes, is a main vent a main vent when it's installed on a radiator?
    NJ Steam Homeowner. See my sight glass boiler videos: https://bit.ly/3sZW1el
  • Hap_Hazzard
    Hap_Hazzard Member Posts: 2,846
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    FYI, a #1 vent port is the same size as a D. The only difference is the fitting.
    Just another DIYer | King of Prussia, PA
    1983(?) Peerless G-561-W-S | 3" drop header, CG400-1090, VXT-24
  • mattmia2
    mattmia2 Member Posts: 9,652
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    You should be able to put some teflon tape on the threads and only screw it in hand tight with the body, there isn't much pressure.
  • dopey27177
    dopey27177 Member Posts: 887
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    To prevent the vent from seeing water collected in the fin tube heating element install it on top of a 6" nipple.

    By raising the vent to a higher location it can prevent a slug of water from damaging the the internal parts of the vent.

    Jake
  • dopey27177
    dopey27177 Member Posts: 887
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    A good fix to prevent water hammer in fin tube convectors.

    Shown is a solution used in a multiple dwelling in 30 apartments.

    The water seal equalizes the pressure on both sides of steam inlets. As you can see condensate flows in one direction out of the steel fin tube convector. Water hammer will not occur in the heating element as all condensate leaves the heating element.

    Be sure to pitch the convector where water will flow by gravity to the outlet side of the convector.
    See attached

    Jake