What typically causes a long, yellow flame on an atmospheric burner?

A long, yellow flame on an atmospheric burner is typically caused by the lack of proper mixing of air and fuel prior to combustion. When air is not mixed adequately with the fuel, there is an insufficient amount of oxygen available for complete combustion. This incomplete combustion leads to the formation of carbon particles, which glow yellow when heated, thereby producing a long, yellow flame. This visual indicator is commonly associated with inefficient burning, and it suggests that adjustments are needed to improve the air-fuel mixture for optimal combustion performance.

Proper premixing of air and fuel is crucial for achieving a clean blue flame, which denotes efficient combustion. In contrast, excessive fuel supply or incorrect burner nozzles can lead to flame irregularities, but the specific characteristic of a long yellow flame primarily points to issues related to air-fuel mixing. Similarly, low atmospheric pressure may affect burner operation in other ways, but it is not the direct cause of the long yellow flame phenomenon.