Method and controller for operating a gas burner appliance

A method for operating a gas burner appliance, the method comprising:

• providing a flow of a gas/air mixture having a defined mixing ratio of gas and air or a defined λ-value to a burner chamber of the gas burner appliance for combusting the gas/air mixture within the burner chamber,
• wherein the gas/air mixture is provided by a mixing device of the gas burner appliance 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 of the gas burner appliance in such a way that a fan speed of the fan depends on a nominal burner-load of the gas burner appliance,
• wherein the fan speed range of the fan defines a modulation range of the gas burner appliance,
• wherein the mixing ratio of gas and air or the λ-value of the gas/air mixture is controlled over the modulation range using a gas regulation valve of a gas armature in order to keep the defined mixing ratio of gas and air or the λ-value constant over the modulation range of the gas burner appliance;
• determining on basis of the nominal burner-load and on basis of the mixing ratio of gas and air of the gas/air mixture or the λ-value of the gas/air mixture a nominal air mass flow in order to provide the nominal burner-load,
• determining the ambient air pressure and the ambient air temperature of the ambient air,
• determining on basis of the ambient air pressure and on basis of the ambient air temperature the atmospheric density of the ambient air,
• determining on basis of the nominal air mass flow, on basis of the determined atmospheric density of the ambient air and on basis of a system resistance of the gas burner appliance the fan speed of the fan in order to provide the nominal burner-load.