Abstract: An apparatus and method for adjusting the air-fuel ratio of a burner in order to minimize the presence of undesirable emissions in exhaust gases of the burner combustion. A burner calibration is performed by selecting a number of calibration points corresponding to burner fuel positions. Air flow is varied for each calibration point as an exhaust gas analyzer determines the content of exhaust gases of the burner combustion. Air settings for optimal combustion are determined for each calibration point and are stored in a programmable logic controller and software. During plant operation, the programmable logic controller and software adjust the air supplied to the combustion of the burner according to the calibration data and the fuel position of the burner.