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Constant Boiler Filling

Fairly new to steam boiler maintenance.  We've lived in our house for 4 years and the first winter here I replaced the Air Vents on each radiator and the main Air Vent in the basement.  I've been doing the regular maintenance I've always done, flushing the steam system, checking valves/water level/pressure.  This year, so far, I need to manually fill the boiler twice a day.  In the past I've filled it twice a week at most.  I know my house is old (1894) and quite inefficient, but I'm not sure why the water level is dropping so quickly and I'm not recovering as much condensate.  Should I install an automatic water feed?  The main air vent seems to be "open" more often than last year, should I replace this first?  It's only 4 years old.

Thanks in advance for your help!

T. Jett


  • crash2009
    crash2009 Member Posts: 1,484
    edited December 2010
    Where is the leak?

    Constant filling usually means you have a leak somewhere.  Of course you knew that, that's why you are here.  Could be in the walls, by the radiators, or the boiler.  Is your sight glass about 6"?  How low is it when you fill it up?  What height do you fill it up to 3", 4", 5", 6" ?  How many inches per week do you have to put in?  The answers to these questions may help narrow things down a bit.  It is also possible, although unlikely, that the wet returns are slowing the condensate return.  Have you, or is it even possible, to clean out the returns? 

    Mark, Yes that's a big possibility.  Buried returns leaking.
  • Mark N
    Mark N Member Posts: 1,115
    Adding Water

    Adding water twice a day indicates that you have a leak somewhere. My neighbor had the same problem. They had a hole in the boiler and their steam was going up the chimney.

    Do the return lines to your boiler run under the floor? They may be leaking. Is your main vent leaking steam? You also state that you were adding twice a week last year. To me that is excessive. My boiler needs water about once a month.

  • BobC
    BobC Member Posts: 5,473
    Hole or a leak


    You said the main vent seems to be working more than it did that year. Does it close when it gets steam hot? Is it just taking a long time to get that hot?

    Check you chimney while the boiler is making steam and see if your getting a lot of white smoke. If you are then you probably have a hole that is letting steam escape into the flue.

    If you don't see white smoke wait for the boiler to cool and flood it up to thae top of the boiler. Then watch for 15-30 minutes to see if water starts to leak out. That indicates a hole above the waterline.

    If neither of those work then you must have leak in a pipe somewhere, steam leaks in piping can be tough to find, is the basement unusually  humid? Old pipes can get porous and let steam bleed through and the steam is invisible to the eye.

    An auto water feeder just makes this kind of problem worse because by the time you realize something is wrong you find yourself with a cellar full of water or fuel bills heading for the moon as you try to heat your town through your chimney.

    good luck,

    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
  • Jettster
    Jettster Member Posts: 20
    Boiler Filling

    I think it's the main vent, it seems to be open longer than I recall.  Talked to my wife and she said I was only filling the boiler every other week, so maybe 2x's a month, felt like more to me, lol. 

    I've traced the entire system, and found a Rad valve that needs repacking, going to do that today as well as replace the main vent.  Didn't see any leaking pipes or joints. only short portions of the system are obscured, less than 2 feet total.  I can't see any traces of water.  I'm going to check out my chimney stack today and see if there is any steam escaping.  Hopefully that's not the case.  If so, that would indicate I would need a new boiler.  The current boiler is a Burnham and was installed in 1999.

    I did find the steam troubleshooting guide on the main site with excerpts from Dan's Book.    
  • crash2009
    crash2009 Member Posts: 1,484
    edited December 2010
    Oh yea,

    I forgot to tell ya.  Start a log book, keep it near the boiler and write down (in inches or fractions of an inch) the time and date you add water.   

    Also, when you are looking for leaks, they may not look like a water leak.  For example, my sight glass leaks and the water evaporates before it hits the floor, but I can see the discoloration on the brass and a bit of white powder between the glass and the rubber.  I had a radiator air vent leaking, it just showed up as a white spot on the carpet.  In the past here there must have been a main vent leaking, because the floor joists were rusty.  My point is, that a steam leak doesn't look like a water leak.  Maybe you knew that all ready.
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