Click here to Find a Contractor in your area.
Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.

Should I Get A Second Main Vent

ksd99ksd99 Posts: 41Member
How do I know if my main vent is working 100%? See attached. Should I add a T and get a second main? The radiators at the end if the main do take longer to warm up, and that is the space where the thermostat is. I do get a little hammering during up at the end of the line.

Comments

  • Jamie HallJamie Hall Posts: 9,773Member
    Well... it's surely working. Whether it's working at capacity is another question. What isn't a question is that it's unlikely -- from the look of the rest of the piping -- that it is anywhere near big enough, even if it is working at capacity.

    But before I go any further, some more questions (sorry). That looks like it's on a return line. So... is this a one pipe or two pipe steam system? If it is a two pipe system, are there crossover traps from the ends of the steam mains out there in the wilderness to the ends of the dry returns? If so, then you surely need more main venting on there -- can you give us some idea of how long the mains are, and what diameter? On the other hand, if this is a one pipe system, is that location where the steam main or mains come back around to the boiler? If so, that's a good enough place for a main vent -- but again, I expect you need more, and the length and diameter of the mains would be very helpful.

    The vent isn't likely to be implicated in the hammering -- that is more likely to be a pipe which has lost some of its pitch, or which has a sag in it. Which, since they are insulated (as they should be!!!) can be a little hard to track down.
    Jamie



    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England.



    Hoffman Equipped System (all original except boiler), Weil-Mclain 580, 2.75 gph Carlin, Vapourstat 0.5 -- 6.0 ounces per square inch
  • FredFred Posts: 7,610Member
    How long is each Main? If all you have is that one Hoffman 75 vent on that return, you almost certainly need more venting. I also see two mains. Is that other main vented at all? Each main should be vented, either at the end of the main, after the last radiator Run-out or on the return.
    It takes 3 or 4 of those Hoffmans to equal the venting capacity of a Gorton #2 and about 6 or 7 of them to equal a Barnes and Jones Big Mouth. For my money, the B&J Big mouth is the way to go. It costs about the same as the Gorton #2 and has twice the venting capacity.
  • ksd99ksd99 Posts: 41Member
    thank you Fred, would I put the big mouth in addition to the Hoffman? I have to be honest I finally got the flow and understanding of the pipes last night, and it occurred to me there is a second main that goes into a crawl space, 2 rads , I will check it out when I return home at the end of the week. I will also measure the mains.
    Again thank you.
  • ksd99ksd99 Posts: 41Member
    Jamie
    It is a 1 pipe system, I should have included it. I will measure the mainswhen I return home this weekend.
  • ksd99ksd99 Posts: 41Member
    Thank you Jamie
  • FredFred Posts: 7,610Member
    @ksd99 , You can add it, in addition to the Hoffman that is on there or, depending on how long that second main is, you may want to move it to that main. Give us the length and diameter of each main and we can better advise you.
  • ksd99ksd99 Posts: 41Member
    Thanks Fred is there away to measure the diameter of the main pipe without cutting into the insulation? As you can tell I am not handy. My new bigmouth will be here this weekend.
  • FredFred Posts: 7,610Member
    Anywhere where there isn't insulation. I see the risers up too the Mains look to be about the same diameter as the main itself. Measure the Diameter there.
  • ksd99ksd99 Posts: 41Member
    here is the length and diameter of the main, I will measure the side main in the morning it is under the crawl space and I will find out if there is a vent there too
  • FredFred Posts: 7,610Member
    Based on this picture, it looks like 70 ft of 3" pipe (your 3.5 is Outside dimension) The last run on that loop, on the left looks like a dry return (actually an extension of the main but no radiator run-outs on it. You need two, better would be three Barnes and Jones Big Mouths, mounted anywhere after the last radiator run out. If I'm reading the drawing correctly, there is a capped pipe on that run, on the left. That would be an ideal location for an antler with 3 Big Mouths installed on it. You will notice a huge difference in the boiler run time and also some fuel savings to offset the cost of the new vents.
  • ksd99ksd99 Posts: 41Member
    Thanks Fred, you are right the last run is the dry run. I wanted to show you pics of the capped pipe, it’s 11 ft then goes thru the wall of the crawl space and then and additional 2 ft. I am also attaching pics of it it looks like the end there’s a t or something. I did order another big mouth so I have 2. Next the question is how And




    what do I need to buy etc....
  • FredFred Posts: 7,610Member
    Take that plug out, install a 3" or so nipple, add an elbow then add another nipple, 12" or so, put a reducing elbow on to take it down to 3/4", add a 3/4" Tee with one Big mouth on the Tee, a 4" to 6" nipple and a 3/4" elbow on the end of the nipple and install your second Big Mouth on that elbow.

    If that fitting, with the plug in it is a 45, use a 45 after your first 3" nipple instead of the 90 degree elbow. Between the 45 that is already there and the new 45, you should be able to turn the antler so it has a slight pitch back to the main so the Big Mouths can drain.
  • ksd99ksd99 Posts: 41Member
    It is actually a T, the bottom of the t is sticking out of the sheet of wood.
    I also took a level to the pipe it slops a bit down at the beginning and in the last pic with the pipe going thru the wall, there is a door to the right of it and a small narrow hall is the entry to the basement.

    I am trying to visualize how this is going to fit there making sure the door can close etc.
  • FredFred Posts: 7,610Member
    ksd99 said:

    It is actually a T, the bottom of the t is sticking out of the sheet of wood.
    I also took a level to the pipe it slops a bit down at the beginning and in the last pic with the pipe going thru the wall, there is a door to the right of it and a small narrow hall is the entry to the basement.

    I am trying to visualize how this is going to fit there making sure the door can close etc.

    That's OK. You can still put an elbow on that Tee and turn it so that it turns away from the door and Parallel to the main, then go up with another elbow and nipple another elbow, a short nipple a Tee (with one vent on the Tee) another short nipple, and the final elbow (with the second vent mounted on that elbow.
Sign In or Register to comment.

Welcome

It looks like you're new here. If you want to get involved, click one of these buttons!