Detecting blockage of a duct of a burner assembly

A control device for a combustion carried out by a burner assembly depending on an ionization-current setpoint, the burner assembly comprising a flame area, an ionization electrode within the flame area, an air-control element to influence a supply volume of air depending on an air-control signal, and a fuel-control element to influence a supply quantity of fuel depending on a fuel-control signal;

• the control device receiving a signal from the ionization electrode and processing the signal into a corresponding actual value of an ionization current;
• the control device generating:
• a first air-control signal transmitted to the air-control element;
• a fuel-control signal by adjusting the ionization current to the ionization-current setpoint based on the corresponding actual value of the ionization current measured by the ionization electrode and transmitting the signal to the fuel-control element;
• a setpoint increased by a specified amount from the ionization-current setpoint;
• a changed fuel-control signal by adjusting the ionization current to the increased setpoint;
• and
• the control device evaluating the changed fuel-control signal generated based on the increased setpoint by comparing it with a specified maximum value and based on the evaluation, identifying a blockage;
• wherein the control device recognizes the blockage if the fuel-control signal generated using the increased setpoint exceeds the specified maximum value;
• and
• wherein the burner assembly comprises an exhaust-gas tract in fluidic connection with the flame area of the burner assembly, and the blockage comprises a blockage of the exhaust-gas tract.