Method of stabilizing gas burner combustion using Fast-Fourier-Transformation (FFT)

Method for operating a gas burner (10) having an air fan (14), a gas valve (17), a gas duct (16), an electrical or electronic sensor (13) coupled to the gas duct and a controller (20). The defined mixing ratio of the gas/air mixture is controlled - by comparing an actual value of a signal provided by the sensor (13) with a nominal value and - by generating a control variable for the gas valve (17) on basis of the control deviation between the actual value and the nominal value, - wherein the signal provided by the sensor (13) is in addition used to determine if the combustion is stable or unstable by processing the time-based signal provided by the sensor (13) in such a way that: -- the time-based signal provided by the sensor (13) is sampled at a defined sampling rate, -- a Fast Fourier Transformation is applied to the samples of the time-based signal thereby generating a frequency-based signal, -- it is determined if the amplitude of the frequency-based signal within a defined frequency range is larger than a defined threshold, wherein --- stable combustion is determined when the amplitude of the frequency-based signal within the defined frequency range is lower than the defined threshold, and wherein --- unstable combustion is determined when the amplitude of the frequency-based signal within the defined frequency range is larger than the defined threshold.