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Steam coming from the main vent

HeatingHelp
HeatingHelp Administrator Posts: 671
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  • edplu
    edplu Member Posts: 20

    I have not fired up my boiler yet for the season so idk how it is but my tenant said last season there was steam coming from the main vent a while into the cycle. I have not seen it yet but I'm trying to get an idea of what would cause this ?? I do not think its normal ?? Thx

  • ethicalpaul
    ethicalpaul Member Posts: 6,069
    edited October 16

    @edplu yes it is a thing that happens, no it is not normal, it is not desirable, and it may indicate the vent has failed.

    NJ Steam Homeowner.
    Free NJ and remote steam advice: https://heatinghelp.com/find-a-contractor/detail/new-jersey-steam-help/
    See my sight glass boiler videos: https://bit.ly/3sZW1el

  • edplu
    edplu Member Posts: 20

    Thx ,,, he said he replaced it last season..guess ill find out when i fire it up ?? If its not the vent waht else could it be ?? TY

  • ethicalpaul
    ethicalpaul Member Posts: 6,069
    edited October 16

    Even a brand new vent can fail (especially recent Gortons even though for some reason everyone hates on Maid O Mist LOL). But another cause can be if your boiler is surging, water can be in the vent affecting its proper operation. Or the dirty boiler water can carry rust chunks that might be preventing the vent from sealing closed.

    Also depending on the orientation of the vent, the vent may not be draining its condensate which also might interfere with the vent's operation, but this would generally be more common on a radiator vent than a main vent, IMO.

    NJ Steam Homeowner.
    Free NJ and remote steam advice: https://heatinghelp.com/find-a-contractor/detail/new-jersey-steam-help/
    See my sight glass boiler videos: https://bit.ly/3sZW1el

  • edplu
    edplu Member Posts: 20

    Its a Hoffman 75 .. what should i do if this happens ?? dhutdown the boiler till its fixed ?? Thx

  • ethicalpaul
    ethicalpaul Member Posts: 6,069

    No, it's not dangerous if it's just leaking a little steam. You want to address it, but the short term issue is the introduction of humidity into your basement and the loss of water from the boiler.

    NJ Steam Homeowner.
    Free NJ and remote steam advice: https://heatinghelp.com/find-a-contractor/detail/new-jersey-steam-help/
    See my sight glass boiler videos: https://bit.ly/3sZW1el

  • HeatingHelp.com
    HeatingHelp.com Member, Moderator, Administrator Posts: 35

    @edplu, we've started a new discussion for you here. Welcome to Heating Help!

    Forum Moderator

    ethicalpaul
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 8,676

    @edplu can you send a picture of the vent in question, in its operating location? Also send a photo of the boiler so we can see the near boiler piping. maybe 2 to 3 different vantage points. High, low, left, right, front… etc

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

  • edplu
    edplu Member Posts: 20

    Sorry i should have open my own trend…i'm new .. Thx all … see pics

  • ethicalpaul
    ethicalpaul Member Posts: 6,069

    You say that Hoffman main vent was replaced last season??

    NJ Steam Homeowner.
    Free NJ and remote steam advice: https://heatinghelp.com/find-a-contractor/detail/new-jersey-steam-help/
    See my sight glass boiler videos: https://bit.ly/3sZW1el

  • edplu
    edplu Member Posts: 20

    ethicalpaul Thats waht he told me but I can not verify that … let me see if I have a close up pic

  • edplu
    edplu Member Posts: 20

    Close up pic Hoff 75

  • Jamie Hall
    Jamie Hall Member Posts: 24,183

    Poor old thing. If steam is coming from it, it's either stuck open — or failed. You could try taking it off and boiling it in vinegar, put that only works sometimes. I'd be very inclined to just bite the bullet and replace it with a Gorton #2.

    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    ethicalpauldelcrossvedplu
  • ethicalpaul
    ethicalpaul Member Posts: 6,069

    It does look a little newer on that closeup but I think you need a new camera :)

    I'm with Jamie (unless it's a relatively short main in which case I would recommend a #1). I'm not sure why people want to install this main vent. It costs a fortune (that might be the reason).

    NJ Steam Homeowner.
    Free NJ and remote steam advice: https://heatinghelp.com/find-a-contractor/detail/new-jersey-steam-help/
    See my sight glass boiler videos: https://bit.ly/3sZW1el

  • delcrossv
    delcrossv Member Posts: 917
    edited October 16

    It's a good pick when you have vastly differing fill rates between two mains.

    Else, yep, just use a Groton #1 (or a Maid-O-Mist) 😉

    Trying to squeeze the best out of a Weil-McLain JB-5 running a 1912 1 pipe system.
  • delcrossv
    delcrossv Member Posts: 917
    edited October 16

    I see the rust stain in the close-up. Replace it. You can get more life out of the next one by adding 6" of nipple out of the top of that tee before you get to the vent.

    Trying to squeeze the best out of a Weil-McLain JB-5 running a 1912 1 pipe system.
  • edplu
    edplu Member Posts: 20

    Thank you all … I fired it up and ran it for about an hour or so, Burrner seemed to run well, LWCO working good, auto feed fill. I followed the heat down the main and all rads (6) eventuly got hot. Air coming out of the vents. I had no steam come out of the main vent yet ?? I did have steam keep coming out of one of the Rad vents ?? Is this vent bad ?? Overall it ran pretty good.. I did forget to check the pressure gauage damm .. next time. It did reach 72 and shut off from the thermo. I thinks it is pretty good to go. If may need burner maintenance. I do

    blowdown weekly to get the juck out… any advice ?? A big THANK YOU folks !!

  • bburd
    bburd Member Posts: 971

    Check your steam pressure during a long run. Post a picture of your pressuretrol (small gray box near the upper part of the boiler, wired into the burner circuit) with the cover off.

    For standard one pipe steam you want the burner to cut out at less than 2 pounds pressure; 1.5 is better. Sometimes the pigtail connecting the pressuretrol to the boiler clogs up and the control cannot sense the pressure. If the pressure becomes too high, condensate can back up in the returns and cause that main vent to leak.


    Bburd
    edplu
  • edplu
    edplu Member Posts: 20

    TY bburd…i will do that next time i fire it up ans post pic .. i didnot check the pigtail yet. I had to spray lub on the fitting b4 i try to take them apart..Thx

  • edplu
    edplu Member Posts: 20

    Are saying once the pressrue reachs 2 lb burner should shutoff even if the termo setting is not reached ?? The burner ran the entire time until it reached the thermo setting..

  • bburd
    bburd Member Posts: 971
    edited October 16

    Yes. Even with the burner off, with steam pressure up the system will continue to heat.

    The pressuretrol should turn off the burner to limit the steam pressure to a safe value if the boiler can make steam faster than the radiators can condense it. This is common because most boilers are oversized.


    Bburd
    edplu
  • delcrossv
    delcrossv Member Posts: 917

    Yes. If the pressuretrol is working there may be several firing cycles before the thermostat is satisfied.

    Trying to squeeze the best out of a Weil-McLain JB-5 running a 1912 1 pipe system.
    edplu
  • edplu
    edplu Member Posts: 20

    I am think now the presuretrol is either clog or bad cuz like i said the burner ran for about a hour b4 it shutdown from the thermostat??

  • Jamie Hall
    Jamie Hall Member Posts: 24,183

    Absolutely. In fact, even 2 pounds is a bit high. And if the pressure goes over that, you run a real risk of damaging or destroying your vents, particularly if it does that a few times.

    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    edpludelcrossv
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 8,676

    It appears that the main steam vent is located at a reducing Tee fitting that is located at the end of the main at the location where the steam would go down the a wet return in this photo.

    It also is threded directly into the Tee fitting. Form what I understand, this is just about the worst place to install the vent. It has something to do with any condensation that may be returning to the boiler at that location may get slammed into the back of that tee and bounce up into the vent. It is said that the best location for a main steam vent is:

    • End of the steam main: Many experts recommend locating the main vent at the end of the steam main, closest to the boiler. This allows for easier installation and reduces the risk of damage to the vent or surrounding piping.
    • At least 15 inches away from the drop into the wet return: Some sources suggest installing the main vent at least 15 inches away from the point where the steam main drops into the wet return. This helps to prevent condensate from entering the vent and reduces the risk of corrosion.
    • 10 inches up from the pipe: Another recommendation is to install the main vent 10 inches up from the pipe, measured from the bottom of the pipe. This helps to ensure proper drainage and reduces the risk of water accumulation in the vent.
    • Return end of any main line: According to one source, a main vent should be located on the return end of any main line, ensuring that the mains are evenly filled with steam and ready to send steam to any branch radiator lines.

    So according to this information, you may want to add a little extra piping to that tee before you install your next vent. here is an illustration that you might be interested in to mediate the poor location.

    It's not the best case scenario, but it is better than nothing

    Finally, the wet return never actually goes down the the "Wet" area. Like it forgot the "Water Trap" part of the Hartford Loop. The left is what you have and the right is what it should be.

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

    delcrossv
  • edplu
    edplu Member Posts: 20

    TY Jamie…that could be why the 1 Rad vent kept blowing out steam ?? or it that vent bad ?? and eventully the main vent will blow out steam too ???

  • delcrossv
    delcrossv Member Posts: 917

    If the main vent isn't already clogged with crud per @EdTheHeaterMan 's comment above or mine above that.

    High pressure guarantees early vent failure.

    Trying to squeeze the best out of a Weil-McLain JB-5 running a 1912 1 pipe system.
    EdTheHeaterMan
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 8,676

    A working vent will never blow out steam. It will blow out warmer air that may get close to the steam, but the steam will close a working vent.

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

    delcrossv
  • delcrossv
    delcrossv Member Posts: 917

    I'd probably do it with a street 45 on the bottom, a nipple and a 45 on the top. Better drainage.

    Trying to squeeze the best out of a Weil-McLain JB-5 running a 1912 1 pipe system.
    EdTheHeaterMan
  • delcrossv
    delcrossv Member Posts: 917
    edited October 16
    1. Clean pigtail and set pressuretrol way down 1.5 psi cutout, 1 psi differential.
    2. repipe main vent as above and put on a new Gorton #2
    3. Get a water seal at the end of the return as @EdTheHeaterMan showed. You have steam flowing both ways in your main the way it's piped now probably making your main vent close prematurely.
    4. replace leaking rad vent.
    5. Test it again. 😀

    Trying to squeeze the best out of a Weil-McLain JB-5 running a 1912 1 pipe system.
    bburd
  • edplu
    edplu Member Posts: 20

    TY Ed !!! This is a very old boiler and has been that way for God knows how long..i bought it thia way .. I was going to put a 6 in pipe extention on the main vent or may do it you way. As far as the piping the Hartford loop is that really necessary due to the age of the system ?? Allso I need to figure out the presuretrol to make sure thats working … Thx

  • edplu
    edplu Member Posts: 20

    Thx Delcrossv … #3 is that the additional piping for the Hartford loop ?? thats a big job ?? if so can i get away without changing it ??

  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 8,676

    #3 is a big job. How long has this system been operating that way? This may be part of the problems you are having. It may also work just fine that way after you solve the other issues.

    Steam is funny that way. You can have a perfect by the book installation and end up with problems that are a result of a poorly designed system or sagging mains or other stuff that has nothing to do with the way the boiler was installed. On the other hand, a total hack job can work without a problem at all. It a strange medium to work with.

    Go Figure!

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

    edplu
  • delcrossv
    delcrossv Member Posts: 917
    edited October 16

    Save it for last and see what happens. Might work fine without one as Ed says. If that crossover pipe is under the waterline, it'll work

    Trying to squeeze the best out of a Weil-McLain JB-5 running a 1912 1 pipe system.
    edplu
  • edplu
    edplu Member Posts: 20

    I think about 35-40 years . Im going to fix the main vent as per your instructions, clean the pigtail and make sure presurtrole is good and that Rad vent. I will probally get rid of the oil boiler before I put alot more $$ into it… its to old .. THX ED…im think maybe mini splits as this is a rancher …

  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 8,676
    edited October 16

    THX ED…im think maybe mini splits as this is a rancher …. OUCH!

    You will want to keep the radiators and boiler in place until you feel the comfort of a mini-split on a cold February morning.

    There is no heat like a steam radiator heat

    EDIT. Story time

    There was an old steam heated church in Ventnor NJ. The church got sold to a different Religious organization that decided that the old steam boiler took up too much room and it was really quite old and needed replacing. They decided on 4 large mini-split units to do that job. The first summer in that old building was awesome, with the new air conditioners. When winter came around, October, November and December seemed to be fine until one day the outdoor temperature dropped below +15°F. could not keep the building above 48°F. That is because the Mini-Split heats with convection. That old steamer heated with radiant. Lots of the mini-split heat was rising to the ceiling, while the radiant heating kept the floor to about 8 feet above the floor at a comfortable 70°F temperature. the space above the people does not need to be heated.

    I got a call from the new owner of the church building to ask how much it would cost to put a steam boiler back in there. Since all the old head knocker pipes in the basement were gone, the price was way over the budget for the next 20 years. Perhaps you can get some noisy gas powered air handlers installed in the choir loft that can blow enough heat in the space, but you will need some vents that will extend up thru the roof to vent them. not such a good look having B Vent chimneys next to your bell tower steeple

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

  • edplu
    edplu Member Posts: 20

    Yea … i figured you would prefer steam !! and you are probably right … thx again for all your help .. i'll keep u posted !!

  • bburd
    bburd Member Posts: 971

    @edplu when you re-pipe that vent, be sure the horizontal pipe is pitched back toward the main so condensate will drain freely.


    Bburd
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 8,676

    Agreed, that is why I turned it back on itself, the pitch should already be in that direction. continuing in the same direction would make the pitch away from the main and collect water. But It needed to be said @bburd. Can't assume anything when dealing with steam. You can also turn to the left or the right if that makes the pitch any better.

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

    edplu