Abstract: A feed forward control system maximizes combustion efficiency in a combustion system, by controlling the amount of excess air supplied to the burner. The feed forward control system includes flow sensors for sensing the flow of air and fuel to the burner. Based upon the fuel flow measurement, a digital computer determines the correct stoichiometric amount of combustion air required and the firing rate of the burner. Based upon the firing rate, the digital computer determines, from stored data in a look-up table, the necessary excess air required. Based upon the stoichiometric combustion air and the excess air, the computer determines the actual air that is required. This air required is then compared with the air flow measurement received by the digital computer. Based upon this comparison, an air trim actuator is driven by the computer until the required air flow is attained.