Method for controlling a heating unit as well as a heating unit and a computer program product for carrying out the control method

The present invention relates to a method for controlling a heating unit comprising a burner with a burner housing, an ionization electrode associated with the burner, and a voltage supply for applying an alternating voltage between the ionization electrode and the burner housing, said method comprising the method steps: applying an alternating voltage between the ionization electrode and the burner housing by means of the voltage supply and correcting the output of the voltage supply in the event of parasitic leakage flows. The object of the present invention is in particular to improve the reliability when ascertaining the air-fuel ratio via the ionization current.