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Firebox turning white

MrBear
MrBear Member Posts: 5
in Strictly Steam
Hello, I have a old coal burning furnace (Thatcher) converted to oil, long time ago.

In the last year, I have a white coating on the top of the firebox? I never had this issue before. Anybody have a clue what is causing this?





Comments

  • BobC
    BobC Member Posts: 5,495
    Is this a steam boiler? Is it off for the summer (not used for domestic hot water)? It might be a leak.

    If it is, overfill the boiler till the steam riser where the stem feeds the mains turns cold. That means the water is up to that level and let it sit there overnight. Chen to see if there is any evidence of water leaking into the firebox. If it is leaking it's time for a new boiler.
    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
  • MrBear
    MrBear Member Posts: 5
    Yes it's a steam boiler. Yes it's off in the summer. Not used for domestic hot water.
  • MrBear
    MrBear Member Posts: 5
    edited October 2021
    Also could I being running to lean? if it's not a water leak? I have no soot.
  • Jamie Hall
    Jamie Hall Member Posts: 24,479
    MrBear said:

    Also could I being running to lean? if it's not a water leak? I have no soot.

    It does look like the combustion is off. How long has it been since you had it properly adjusted with the test instruments? It can't bee done by eye... and no soot is not necessarily a good criterion, either.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • MrBear
    MrBear Member Posts: 5
    That's my first thought, combustion is off. It was done by eye.

    I maintenance the system every year but have not messed with air mixture recently.
    Could that be the problem instead of a leak?






  • Jamie Hall
    Jamie Hall Member Posts: 24,479
    "By eye" my thought is that it's running lean. However, as I said, it's quite impossible to get it really properly dialed in without using combustion test equipment. The problem is that it may takes or weeks of running to change any patterns in the firebox, never mind just looking at the flame and saying "yeah, that looks good".

    Find someone with proper measuring and testing equipment who knows how to use it -- and let them have at it.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 16,248
    Yes, to lean, too much air. Find a tech with an analyzer
  • HVACNUT
    HVACNUT Member Posts: 6,210
    Is there a Firomatic valve nearby?
  • MrBear
    MrBear Member Posts: 5
    HVACNUT
    No, I don't have a Firomatic valve nearby.

    EBEBRATT-Ed
    Yes, I'm leaning that way and maybe change the nozzle out, which this will be the second year of using the same nozzle.

    I'm looking into another possible explanation for the white stuff.

    Lynn Manufacturing makes the white combustion chamber. I remember talking to technical support and was told that you should see a nice red glow in the chamber at the end of your burning cycle. The red glow reflects back on to the fire to complete the burn. Then the chamber should cool down. I do have a nice glow to the chamber when it shuts off. This is a free standing chamber, but you can brace it with something. So I use vermiculite around the chamber because it doesn't burn.

    I wonder if I'm using to much vermiculite, causing to much heat and making the white Combustion Chamber below flake off and bake on the firebox above? The chamber below has surface cracks in the inside of the chamber. The cracks do not go all the way through the chamber.

    Also, the iron is in good shape.




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