METHOD AND CONTROLLER FOR OPERATING A GAS BURNER APPLIANCE

Method for operating a gas burner appliance (10), by providing during an actual burner-on-phase of the gas burner appliance (10) in request to an actual nominal heat demand a flow of a gas/air mixture (M) to a burner chamber (11), the gas/air mixture (M) having a defined mixing ratio of gas (G) and air (A), wherein said gas/air mixture (M) is provided by a mixing device (25) mixing an air flow with a gas flow, wherein the air flow or the flow of the gas/air mixture is provided by a fan (14) in such a way that a fan speed of the fan (14) depends on the actual nominal heat demand, wherein the fan speed range of the fan (14) defines a modulation range of the gas burner appliance (10), wherein said defined mixing ratio of gas (G) and air (A) of the gas/air mixture (M) is controlled by a controller (26) using as input a signal provided by a sensor (13) and providing as output a control variable for an electric or electronic gas flow modulator (18) in order to keep the mixing ratio of gas (G) and air (A) at the defined mixing ratio over the modulation range of the gas burner appliance (10). If the actual nominal heat demand of the gas burner appliance (10) is no longer present the following steps are automatically executed in order to set-up the gas burner appliance (10) for an upcoming burner start: Decrease during the actual burner-on-phase the fan speed of the fan (14) to a defined fan speed while keeping the mixing ratio of gas (G) and air (A) of the gas/air mixture (M) at the de-fined mixing ratio thereby decreasing the opening position of the gas flow modulator (18). Keep the gas flow modulator (18) at said decreased opening position and terminate the actual burner-on-phase of the gas burner appliance (10).