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Losing Water from Burnham v85

bowman Member Posts: 20
Have a 20 year-old Burham v85 that is now losing water.
In past years, never had to add water more than once every six week or two
months during winter.
So far this year, am adding water every week.
Checked all vents, on mains and radiators - no leaks.
Checked all radiator valves - no leaks.
Checked all puping - no leaks.
No water or water stains under or around boiler.
No obvious steam vapor coming our of chimney when running.
No new sounds or issues - heats fine, just losing water.

Where else should I look?
Any ideas?

Thank you


  • ethicalpaul
    ethicalpaul Member Posts: 5,701
    Fill the boiler to the header and let it sit for some hours to see if there's a leak in the boiler itself

    Then lower it to a high point on the gauge glass and mark it. Let it sit for some more hours and see if it moves. If it does, then you are losing water from the wet return.

    if it doesn't, then you probably do in fact have a steam leak, check everything again :sweat_smile:
    NJ Steam Homeowner. See my sight glass boiler videos: https://bit.ly/3sZW1el
    Long Beach Ed
  • bowman
    bowman Member Posts: 20
    Okay. Took your advice.

    Filled above sight-glass - confirmed leak.
    Started to leak out just as water level approached the very top of the sight glass.
    Removed top cover and can see wetness about 1 inch below top of section 4.
    Confirmed rust stains inside firebox above in that same location where drips were coming down.

    Will try to limp thru heating season and replace in spring.
    In meantime, is there anything I can add to the boiler to slow that leak?
    Have heard of commercial sealers.
    Have also heard of folks using oatmeal. (??)

    What do you experts recommend to limp along until ready to swap?

    What and how much?

    Please advise


  • Jamie Hall
    Jamie Hall Member Posts: 23,270
    edited December 2022
    Sealers don't work all that well -- and they won't work at all above the water line. They can't get there. Oatmeal worked OK on Model A Fords, but not much of anything since then...

    Limp along, but remember that a leak never gets smaller, so start finding a good contractor (where are you? We may have someone we could recommend) and get him or her lined up to go.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • ethicalpaul
    ethicalpaul Member Posts: 5,701
    edited December 2022
    If it were me and I could see the area I would probably wire brush away the loose stuff and try a fiberglass/jb weld patch of some kind to get through the season (works best if your pressure is low as it should be)

    I'm glad you found it, knowing is half the battle
    NJ Steam Homeowner. See my sight glass boiler videos: https://bit.ly/3sZW1el
  • Long Beach Ed
    Long Beach Ed Member Posts: 1,202
    That boiler should last more than 20 years.