A method for determining an change in an operating condition of a gas burner appliance. In some instances, a calibration of a gas/air mixture may be performed when the combustion quality of the gas burner appliance diminishes. This may be accomplished by adjusting a throttle position of a throttle valve that throttles the gas to the gas burner appliance. After calibration has been performed, a throttle position of the throttle valve is determined, and based on the throttle position determined after calibration, a change of an operating condition of the gas burner appliance is detectable.