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Can a steam trap be used as a mains vent?

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Rusty2
Rusty2 Member Posts: 69

I was one of many who jumped at the Barnes & Jones Big Mouths and put them at the ends of my mains to get the air out fast. They seemed to work great…for awhile. While searching for the Mepco/Dunham Bush 2E thermostatic disc with a 1" plug to replace in 3 of my Big Mouths that had failed, I realized (I'm a dumb home owner) that I was using a steam trap as an air vent on my mains. Is this OK to do? Because I have single pipe steam (and am not in the trade) I didn't recognize the B&J's as steam traps. If I had 2 pipe steam I might have seen steam traps on the return sides of my radiators. Of the companies make steam traps, as far as I have found, only Barnes & Jones marketed them as Mains Vents. Is it recommended or OK to use a steam trap as a mains vent? Thanks

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  • ethicalpaul
    ethicalpaul Member Posts: 5,702
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    They took one of their traps and modified it to work as a main vent, the purpose for which it was offered. If it's open to air and closed to steam, then you have a main vent, no worries.

    NJ Steam Homeowner. See my sight glass boiler videos: https://bit.ly/3sZW1el
    Rusty2
  • Mad Dog_2
    Mad Dog_2 Member Posts: 6,926
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    Yes...Its America...you can do what you want in your own 🏡 home! Many of us have done this. I for one have not seen 1 failure of the B & J Bigmouths and I've put in alot the last 6 yrs or so. I'm currently doing a little simple experiment to see which will house up longer? The Gorton #2 or the Bigmouth. Have a Mad Dog battery of Each in one building . Even if they do fail after a while, they are so easy swap the capsule or whole trap. Mad

    .

    Rusty2
  • 109A_5
    109A_5 Member Posts: 1,385
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    Hello @Rusty2,

    Why not just repair it or them. Traps are repaired or rebuilt all he time, that is one of the benefits of that design.

    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
    Mad Dog_2Rusty2question
  • Mad Dog_2
    Mad Dog_2 Member Posts: 6,926
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    Exactly 💯 %.. but if you're lazy...replacing it is even easier Mad

  • Rusty2
    Rusty2 Member Posts: 69
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    Thanks Mad Dog, Paul and 109. Just wanted to make sure I was doing the right thing. I guess a steam trap is the closest thing to opening the main full port and then closing it when it fills with steam. Seems like the fastest way to vent. If this is the case why would we use anything else to vent the mains more slowly? Is there any reason to vent the mains at a slower rate? I also have Gorton #2's, but have never taken them apart. They never failed.

  • Jamie Hall
    Jamie Hall Member Posts: 23,286
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    Using a trap as a main vent for a steam main is hardly new. Most vapour systems vented their mains into the dry returns with steam traps… only we call them crossover trpas in that application.

    Depending on the system, the dry returns, in turn, were vented with BIG main vents, or into the open air with an open pipe.

    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Mad Dog_2
    Mad Dog_2 Member Posts: 6,926
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    Gorton #2s may come apart but they ain't goin back together. I for one have never seen a Steam trap serving as a main vent at the end of a wet or dry return except here or on my own jobs. Its a matter of preference, but I use mostly #2s because when Big Mouths do fail there going to spit condensate much more than Gorton. Mad

    Rusty2Long Beach Ed
  • Jamie Hall
    Jamie Hall Member Posts: 23,286
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    On systems with a steam trap servicng the purpose of a main vent, it is referred to as a crossover trap, and its outle connects directly the assonciated dry return. Veru common. On many oder systems, the same traps were used for radiator traps and for crossover traps — the airflow capacity is ample.

    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    Mad Dog_2Rusty2
  • Mad Dog_2
    Mad Dog_2 Member Posts: 6,926
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    I agree Sir Jamie..

    Just never seen a Trap as the FINAL EXIT port of the air out in the field until I think Gerry Gill & Steve Pajeck and Steamhead tried it...Then the craze started. Mad 🐕 Dog

    Rusty2
  • JohnNY
    JohnNY Member Posts: 3,230
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    I've had exactly zero percent success with Big Mouth air vents but I realize I'm in the minority. Mine all eventually leaked. A lot. Different applications, jobs, locations, etc. Never again. Does anyone know what the modification was and if a Big Mouth will still work well as a trap?

    Contact John "JohnNY" Cataneo, NYC Master Plumber, Lic 1784
    Consulting & Troubleshooting
    Heating in NYC or NJ.
    Classes
    Rusty2ethicalpaul
  • Rusty2
    Rusty2 Member Posts: 69
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    Thanks Jamie. As a crossover trap would it be mounted vertically on a nipple with the exit port piped back into the main. Or would it be mounted horizontally off a nipple with a street 90 so that the exit port faced down going back into the main via a union?

  • Rusty2
    Rusty2 Member Posts: 69
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    Yes JohnNY, mine all leaked too. I only had 3 of them and was wondering if I should cut my losses and just use all Gorton #2's.

  • ethicalpaul
    ethicalpaul Member Posts: 5,702
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    I have a 100% failure to close rate, but that was a sample size of one

    NJ Steam Homeowner. See my sight glass boiler videos: https://bit.ly/3sZW1el
  • Jamie Hall
    Jamie Hall Member Posts: 23,286
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    The mounting is you go up vetrically off the main with a nipple — typically six inch. Then horizontally to the trap inlet, however long as may be (abain, typically six inchwa or so) to trap inlet. Then vertically down from the trap outlet to the dry return with another nipple.

    If the main is parallel flow — they usually are — there will also be a drip to a wet return close to floor level at about the same location, and since the main and dry return are almost always parallel, there will be one from the dry return down to the wet return at the same location.

    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    Rusty2
  • Rusty2
    Rusty2 Member Posts: 69
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    JohnNY, as far as the modification to the Big Mouth goes, I believe this is Sailah, making the demonstration in the video, who used to work at B&J. I could be wrong. It may be someone else. He put an O-ring at the exit port for a better seal. Mine all had this O-ring and initially worked well, but after a season they started to leak.

    CLamb
  • STEAM DOCTOR
    STEAM DOCTOR Member Posts: 1,967
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    I had some good ones and some failures. Too many failures to be worthwhile. I would have to go back and replace every failure on my own dime. I was able to get replacements for free but there's no compensation for the time and labor. I had some that worked fine and started to leak afterwards. When I say leak I mean steam leaks. Not water leaks. Too much headache. Not worth it for me. And I was one of the biggest big mouth fans in the early days.

    ethicalpaulJohnNYLong Beach Ed
  • jumper
    jumper Member Posts: 2,248
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    Can't match human operated valves. Open 'em up; let the air out; close 'em.

    Can say the same for boiler control. Fire it up; shut it off.

    I think some ships in olden days were operated something like that?

    Rusty2
  • Rusty2
    Rusty2 Member Posts: 69
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    Steam Doctor, the free replacements from B & J are a thing of the past.

  • Mad Dog_2
    Mad Dog_2 Member Posts: 6,926
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    News to me. I guess I got all good batches. How hard could it be to correct them in production? Unfortunately, that means that one too many went you and got installed without anyone even knowing because use as a regular trap, you're not going to SEE the steam & condensate spitting out in the open.. its all hidden in the pipe. Mad

  • mattmia2
    mattmia2 Member Posts: 9,640
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    Didn't someone on here replace the o-ring with a material more suitible for steam?

    Some but nto all main vents have a float that will block water, that is probably the biggest functional difference.

    @Erin Holohan Haskell this new text box won't spell check on chrome.

    Erin Holohan Haskell
  • Hap_Hazzard
    Hap_Hazzard Member Posts: 2,846
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    He should have rolled a lip over the o-ring. I guarantee it won't stay put. Neoprene and brass have very different expansion rates.

    Just another DIYer | King of Prussia, PA
    1983(?) Peerless G-561-W-S | 3" drop header, CG400-1090, VXT-24
  • 109A_5
    109A_5 Member Posts: 1,385
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    My Big Mouth came with the O-Ring not properly seated in the grove, you could see it through the inlet port. I believe it would not work correctly as received. I emailed B & J, no response. I hate to return things. So I just bought some used sockets and took it apart (I did not want to use pipe wrenches).

    Once the O-Ring is properly installed in the grove it is very hard to get back out. You have to roll it into the grove, not just push it in.

    Additionally, measuring the groove and the O-Ring (curiosity and for future maintenance purposes) I believe the O-Ring B & J chose is actually one size down from the groove dimensions thus aiding to it staying in place with a little elasticity of the ID (Inner Diameter) of the O-Ring.

    Since over the years I believe B & J has had various revisions to this product, so others may be different than mine.

    Also; I did not like the way the brass disk on the expanding capsule flopped around rubbing across the O-Ring on each closure so I put 3/16" piece of silicone tubing behind the brass disk to support it so it is more square to the port and the O-Ring and still has some settling looseness.

    So far so good.

    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
    Mad Dog_2
  • STEAM DOCTOR
    STEAM DOCTOR Member Posts: 1,967
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    B&GJ went through a few modifications/redesigns. I think I gave up after the second one. And I really loved the Big Mouths. I was advocating for them long and hard in the beginning. The ones that worked were truly awesome. But I could not keep up with the call backs. Had some customers with damage. Wanted to know why the living room walls were turning brown... These days I just carry carry Gorton 2's, 1's and Hoffman 75's. Have had the occasional failure here and there but not much to speak about.

    Mad Dog_2JohnNY
  • STEAM DOCTOR
    STEAM DOCTOR Member Posts: 1,967
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    Had the stuck number two every once in awhile. But really not often. And those I knew about before I showed up at the job sites

    Mad Dog_2