The presence of air bubbles in a fuel line can cause what effect on burner operation?

The presence of air bubbles in a fuel line can lead to flame instability during burner operation. When air is introduced into the fuel line, it disrupts the consistent flow of fuel, which is critical for maintaining a stable flame. This fluctuation in fuel delivery can cause variations in the combustion process, leading to an inconsistent or unstable flame. A stable flame is essential for efficient and safe operation of the burner, as it ensures that the fuel is burning evenly and at the intended rate. In cases where flame instability occurs, it can also lead to incomplete combustion, increased emissions, and potential safety hazards.