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airvents ?

jonny88 Member Posts: 1,139
Was working in a house on a gas leak,homeowner asked me to look at his boiler.Gauge glass had no water but feeder would not feed.I took apart gauge glass,pressuretrol etc.Everything was clogged solid.I cleaned and filled boiler and now gauge glass shows water level.It's a Carrier steam boiler.The installers never left a valve to empty boiler water.On the bottom of boiler there is a 2 1/2 inch plug.?1 ..can i remove it and put a full port valve there to blow down boiler.

?2..the pressure gauge 0-25 is broke and stuck on 5psi.Most of the air vents on rads dont work.If I replace all air vents is it as easy as say put all D valves on top floor ,C valves on 3rd floor etc.In the foyer there is a 5column 28 section rad,what kind of airvent should that get.

House was built in 1890 so as you can imagine a lot of work has been done,thanks for your help.


  • Jamie Hall
    Jamie Hall Member Posts: 15,443
    It's really amazing sometimes

    how badly maintained a steam system can be and still work!  As least after a fashion.

    If you can get that plug out, I should think you could put a blowdown on there.  Probably not a bad idea.

    I'd also take the low water cut out apart and stare at it (assuming it has one); it may or may not work properly any more.

    You need a 0 to 30 psi gauge to keep the insurance folks happy, so you should replace that busted one.  You could throw a T on the pigtail, though, and add a 0 to 3 gauge at the same time, just to see what is happening.

    Are there main vents?  if not, putting them on will help a lot, and make balancing the system a lot easier.  Your suggestion of radiator vents is a place to start, but you may find you need to go to slower or faster (more likely slower) to get the thing really balanced.

    Bet you save a lot of fuel though, when you get done...
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • jonny88
    jonny88 Member Posts: 1,139

    Thankyou for your quick reply.I will be replacing the main air vents as both are also leaking.
  • nicholas bonham-carter
    nicholas bonham-carter Member Posts: 8,428
    Main vents

    Definitely put on a 0-3 psi gauge ( along side a new 0-30 gauge, as that will show you the back-pressure of main venting. You want the new main venting to approximate the low back-pressure of an open pipe as possible.

    As you won't probably be able to run the system much before next winter, I would suggest some gorton 2's as a replacements. Leave the present radiator vents in place, as they seem to last longer than the mains even when over-pressured. At the start of winter, you can see if there are obvious signs of non-working radiator vents.

    Set the pressure as low as you can on the pressuretrol, and check the pigtail for obstruction as you mount the gauges.

    A full-port ball valve could serve as the new boiler drain.--NBC
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