What indicates that a burner needs a primary air adjustment?

A burner requires a primary air adjustment when it is producing yellow flames. Yellow flames indicate an improper air-to-gas ratio, which can result from insufficient primary air mixing with the gas before combustion. This deficiency leads to incomplete combustion and the formation of carbon monoxide or soot, which is highlighted by the yellow color of the flames.

In contrast, blue flames are typically a sign of optimal combustion, suggesting that the burner has the correct air-to-gas mix. Floating flames may also indicate an air adjustment is necessary, but they are not as definitive as yellow flames in presenting a problem. Consistent pressure readings alone do not provide sufficient evidence of combustion efficiency or air adjustment needs, as they do not encompass the actual quality of the flame being produced. Thus, yellow flames are a clear indicator that adjustments to the primary air are required to ensure safe and efficient burner operation.