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Yellow Smoke Spot

EdTheHeaterMan
EdTheHeaterMan Member Posts: 9,130
What causes the Yellow/Amber smoke spot on an oil burner smoke test? Is this an indication of a combustion problem that should be corrected? How do you go about correcting the problem?

Edward Young Retired

After you make that expensive repair and you still have the same problem, What will you check next?

Comments

  • Yellow Smoke Spot

    excessive air causing un burned fuel to pass to the flue. Cut back on your co2 a half a degree and check again (reduce air)

    al
  • A-TEAM
    A-TEAM Member Posts: 1
    yellow spot

    it could very well be too much air. but it could also be either the wrong spray pattern,and or degree(wrong nozzle). even the end cone or retension head may be carbon'd up.
  • Steve Ebels
    Steve Ebels Member Posts: 904
    Another thing

    I've run into a yellowish discoloration caused by condensation. Once in a while with a good furnace (thermopride) and a good burner (riello) on the right duct system, I've had efficiencies get up in the high 88% range causing moisture in the flue gas. I don't know if that's what you have there but we've seen it more than a few times. They just have to be opened up a tad on the air shutter and it disappears at the expense of a point or two in efficiency.
  • john_35
    john_35 Member Posts: 29
    yellow smoke

    Yellow smoke readings usually mean too much air. What's the O2 or CO2 reading? If carbon dioxide is low (or oxygen is high) you need to close the air shutter a little at a time til it cleans up. CO2 below 8% is low. You didn't mention what type of burner you have; is it flame retension?
  • SteveB
    SteveB Member Posts: 19


    I would be looking for an impingement in the combustion area especially near the retention ring or you have way too much air to the flame. Try running at about 11 1/2% CO2.
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