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Vents hiss loudly with new boiler

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Barbara
Barbara Member Posts: 4
in Strictly Steam
On our one-pipe steam system, we replaced a 60 year old oil-fired boiler with a gas-fired Peerless Series 63 cast iron boiler. The old boiler took forever to heat but did it quietly with no clangs, knocks, gurgles or vent hissing. The new boiler zooms the heat through the house in a few minutes (.5 -1.5 psi) with no clangs, knocks or gurgles but the vents hiss so loudly that they wake everyone up from sound sleep.  The main is vented with a new Hoffman 4A quick vent (I don't know what was originally used).  The room radiators are vented with Hoffman 1A vents set according to radiator size.  We replaced the old Hoffmans with new ones, thinking that might help, but it didn't.  Any suggestions or do we need to buy earplugs to get a good night's sleep in the deep cold of January?

Thanks

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  • Rod
    Rod Posts: 2,067
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    Need more Main Venting

    Hi- You need more main venting. . According to Gerry Gill's excellent venting chart, the Hoffman 4A vents .133 cu.ft /min , The Gorton # 1 vents  .330 cu.ft /min and the Gorton #2 vents 1.100 cu.ft/min   If you have room/clearnace  I'd install a Gorton #2. The hissing is because the radiator vents have to vent all the air from the mains due to the present  main vent (the 4A) being  too small. Also you might want to check you boiler pressure . It should be operating at under 2 PSI.

    - Rod
  • Steve_175
    Steve_175 Member Posts: 238
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    How many feet

    of mains do you have? This is the main pipe that loops around the basement. You may also have more than one loop. The suggestion of adding a Gorton #2 is what I would do but you may even need to add two or three of them in an 'antler' configuration.

    Also are your pipes insulated?
  • Barbara
    Barbara Member Posts: 4
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    Vents hiss loudly with new boiler

    90 feet of main, only one main loop, with 1.5" of fiberglass insulation (asbestos removed and replaced).  I looked at Gill's chart and agree that a larger vent is needed by those calculations.  Thanks - I'll try that and report back to the wall. 
  • Barbara
    Barbara Member Posts: 4
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    can a main vent be TOO large?

    We have 90 feet of 2 1/2" main loop, with 1 1/2' insulation.  That's about 2.7 cubic feet of air to vent.  The boiler seems to run about 2-3 minutes so a Gorton #2 seems appropriate.  But can a main vent be TOO large?  
  • Rod
    Rod Posts: 2,067
    edited December 2010
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    Main Vents

    Hi- Generally you can't get into any trouble with "too much" venting on the main vents. Radiator vents are another story. Here's a link to Gerry Gill's website and his page on venting that might be of interest to you.You might want to take a look around his website. He has a lot of other intersting info there.

    http://www.gwgillplumbingandheating.com/webapp/GetPage?pid=415

    - Rod
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