A method for evaluating a quasi-stationary pressure difference detectable by a sensor at a gas boiler. The gas boiler has a mixing device (4), a fan (5), a main flow regulator (3), a control valve (2) and a safety valve (1). The sensor detects a differential pressure between a pressure (p2) at a measuring point upstream of the main flow regulator (3) and downstream of the control valve (2) and a reference pressure (p0, p1) at a reference measuring point. The sensor transmits a signal to an electronic evaluation system. The electronic evaluation system compares the differential pressure during a pre-purge phase, wherein the safety valve (1) is closed, with the differential pressure after the pre-purge phase and detects an error by the comparison.

A combustion system including a bypass which opens to the open air during two different operating modes (conventional combustion; oxy-combustion), and which has the function, on the one hand, in the two operating modes, when the discharge valve is at least partially open and the recycling valve is closed or open, of allowing air to enter the recycling loop, and which has the function, on the other hand, in the second operating mode, when the discharge valve is closed and the recycling valve is open, of allowing a surplus of the combustion gas produced by the combustion device to be discharged from the recycling loop, the other fraction of the combustion gas produced by the combustion device supplying the mixer.

A premixing apparatus that mixes a fuel gas with air and supplies an air-fuel mixture in a burner through a fan includes a control device that is configured to carry out a third control that: calculates and memorizes a lower limit of a rotational speed of a fan, at which an increase of an opening degree of a variable throttle valve becomes necessary, as a first threshold; and when the rotational speed of the fan increases to the first threshold or faster next time, immediately changes the opening degree of the variable throttle valve to an increased opening degree, which is larger than a predetermined standard opening degree and is obtained by multiplying a deviation of the rotational speed of the fan from the first threshold by a predetermined coefficient.

Various embodiments include a method for regulating a burner appliance comprising a combustion chamber, an air supply duct with an actuator to adjust the air supply, and a fuel supply duct with a fuel actuator to adjust the fuel supply. The method comprises: determining the value of the air supply V L; determining the value of an air ratio ; providing an individual scalar fuel parameter h; calculating the power output P_ist of the appliance based on the air supply V L, the air ratio , and the individual scalar fuel parameter h using P_ist=h/.Math.V L; and regulating the burner appliance with the fuel actuator and the air actuator until the actual value reaches the target value.

An electronic control device includes: a flow rate calculation unit that calculates a flow rate of intake air based on an output signal of a flow rate measurement device assembled to an intake pipe; a flow rate correction value calculation unit that calculates an average value, a maximum value, and a minimum value of the flow rate of the intake air, calculated by the flow rate calculation unit, during a predetermined period, and an amplitude of a signal with one or more frequencies equal to or higher than a fundamental frequency of the output signal of the flow rate measurement device and included in the output signal of the flow rate measurement device, and calculates a correction value for the flow rate of the intake air based on calculation results; and a flow rate correction unit that corrects the flow rate of the intake air based on the correction value.