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Main Vents

There is a vent on top of my header (see photo).  Should I remove this and plug it?  I am trying to figure out how much main venting I need, and how to install them.  My boiler is 150,000 btu gross hooked up to 7 radiators equalling 416 sq ft of EDR.  Will probably order that publication on here describing all the vents, just gotta find my $5 coupon I got with "Greening Steam".  


  • FredFred Member Posts: 5,278
    edited March 2014

    That vent can't possibly do anything. It has to close as soon as the boiler cycles, if it ever even opens. Is that the equalizer below it or a riser? I'm assuming it is the equalizer. I'd take that out, as you suggest and plug the opening. Make sure you have good venting at the end of your main or in the return. What is that on the other end, above your riser?
  • JStarJStar Member Posts: 2,668

    I used to work with a plumber who would install vents on the near boiler piping because it made the water line more stable. What he didn't say publicly was that his waterlines were incredibly unstable because of his horrible piping practices.

    I'll bet that once the vent is plugged, you'll see a disappearing waterline or some other quirk. The vent is not a good answer to the problem, but a very good mask.
    - Joe Starosielec
    [email protected]
  • BlossBoilerBlossBoiler Member Posts: 5
    3/4" main

    On the right side of the photo is a main pipe that is only 3/4" iron pipe that leads to my smallest radiator.  It is a tube style 17.5 EDR that has its vent on top.
  • BlossBoilerBlossBoiler Member Posts: 5
    edited March 2014
    Low Pressure Gauge

    Another quirk of my system is the low pressure (0-32oz.) gauge reads below zero when the system is cold.  You can see the gauge in the bottom of the photo in my first post.  I can understand why this might happen when the steam is condensing, but after the whole system is cold it should be back to 0 oz/, right?
  • FredFred Member Posts: 5,278
    edited March 2014

    Was/Has that gauge been calibrated to 0? If you take it off of the pipe does it bounce back to 0? If so, I would suspect the pigtail that the Pressuretrol and gauge are mounted to is plugged up and when the boiler cools down, the condensation in that pigtail is creating a vacuum. Take the pigtail off and clean it out as well as the opening it is mounted to and the pin hole in the Pressuretrol.

    I would think that 3/4 inch radiator run should be moved from of the top of that Boiler riser/header and be tied into the actual main line if possible. Do you get any water hammer? It would seem condensate would run back towards that riser/header and cause some hammer. if you do move it to somewhere along the main, I would use 1 1/4 inch pipe. What size radiator shut off valve is on that radiator?
  • BlossBoilerBlossBoiler Member Posts: 5
    small radiator

    the supply valve to that little radiator in my kitchen is 1".  I'm not gonna mess w/ the piping though.  I have very little water hammer, sounds more like a tick tock than a hammer.  Although there is 1 main pipe that pitches the wrong way and I plan to fix that.  Probably gonna shorten the riser from the boiler to get that main to pitch correctly.  the riser had a leak when i 1st bought this chateau (had no clew about steam heat), so i hired a plumber to fix it and i think he replaced it with a straight pipe that is too long which made it pitch towards the radiators.  Just ordered Gerry's venting "book".  Hope that helps me figure out venting on the mains and rads. 

    thanks for your advice Fred
  • JasonJason Member Posts: 294

    The bigger problem that I see is the Bullhead T on the supply that should be broken into two risers. It's kind hard to see from the picture but it looks like the tee going up to the system riser is between two risers coming out the boiler. Both of these are no no's in steam piping.
  • BlossBoilerBlossBoiler Member Posts: 5
    I have a 1 pipe steam system and am trying to figure out if it's counterflow or parallel. I think it is parallel to two of the radiators, and counterflow to the other 5 radiators. Is that possible?
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