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Steam from chimney

Don_175 Member Posts: 125
Have a 6 year old boiler.  It has added about 3 gallons of water since the season started. With this super cold weather we are having in Ohio, it has been adding about a gallon per month. I just happened to be outside recently and saw some steam around chimney. Not a huge amount but it is visible. But it’s also been about 20 degrees. Is that normal? How much should one expect to see as far as water usage if a boiler has a leak above water line? Thanks 


  • Jamie Hall
    Jamie Hall Member Posts: 23,271
    Some condensation and visible steam is quite normal, particularly in colder, more humid weather. If you are only adding a gallon a month, you don't have a problem.

    To answer your question directly, a leak above the water line is likely to result in gallons --that's; plural -- per day.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Don_175
    Don_175 Member Posts: 125
    Thanks Jamie. That’s what I was thinking but I’d never seen steam coming out of chimney before. Must be because it’s been so cold. 
  • bburd
    bburd Member Posts: 912
    Gas fired systems will show visible vapor at the chimney or vent in cold weather, due to the very high moisture content in the exhaust gases. This is normal.

  • Big Ed_4
    Big Ed_4 Member Posts: 2,780
    What you want to see is a clear space between the top of the chimney and where the condensate starts ...
    I have enough experience to know , that I dont know it all