Oil Burner Combustion Flame Colour

It has been some years since I operated a boiler, but since no one else has replied so far, here is my recollection:

The inspection port probably won't let you see close to the nozzle, where there might be some blue to the flame. Then for a way the flame should be almost clear, grading to a light straw yellow, a bit darker toward the end of the flame. The flame should be symmetrical and not impinge on metallic parts (as would happen with the wrong spray angle, for instance). There should be almost no visible smoke from the stack.

The stack temperature will vary with the saturated temperature/pressure of the steam (if memory serves, about 50°C or 90°F higher). Too high suggests tube fouling, either scale on the water side or soot on the fire side. Too low suggests too much excess air or poor fuel delivery.

Oddly, an older steam plant textbook of mine says very little about this.

'...Too low suggests too much excess air or poor fuel delivery....'

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That's curious. Running too lean improves heat transfer? I'm not trying to give you a hard time, just having trouble figuring out how that happens...

I think he is pointing out the fact the to much excess air will have a cooling effect on the transference of heat into the water. Time, Temp, Turbulence. In the case of hand firing you have four distinct zones, Starting up from Ash to Oxidation ...up to Reduction....then Distillation ... Finally Combustion.

Beyond the first portion of the first sentence, I don't understand what you have written. Looking at that first sentence, you lost me at 'cooling effect on the heat transference'. Perhaps you can rephrase?

Straw, That is the correct color for steam atomizing burners. I have to give Mr Tornado a GA. Mr Dhayanandhand is not wrong about White intensity, but Straw is the right color. Now I will have my humble pie with a serving of Black coffee please.

In addition to #1, keep the exit temperature of the stack above the dewpoint of sulphuric acid, ~135degC. Otherwise the stack will rot in short order.

All burners perform four functions, Deliver the fuel to the combustion chamber, Deliver air to the combustion chamber, Mix the fuel with the air, Ignite and burn the mixture. How that is done for oil in your case, we will have to guess. If you don't have a proper flue gas analyzer and are relying solely on flame color and shape, I would say most oil burners, of the atomizing type should produce a Lemon color flame and a bushy shape.(Flame shape is dependent on burner and combustion chamber design). If stack temperature is 150 F over steam/water temperature, its to high. Tube cleaning or burner adjustment are your solutions. High stack temperature means wasted heat. On the other hand if this is a vertical rotary sunflower oil vaporizing flame burner, then Orange is the color of choice, and ignore every thing I said previous.

Dear Mr.babasiga, If furnace oil is used the colour should be BRIGHT WHITE. If Gas is used, the colour should be BLUE. DHAYANANDHAN.S