Method for evaluating a quasi-stationary pressure difference detectable by a sensor at a gas boiler, and associated gas boiler

A method for evaluating a quasi-stationary pressure difference detectable by a sensor at a gas boiler, the sensor is a differential pressure sensor or a mass flow sensor, the gas boiler has a mixing device, a fan, a main flow regulator, a control valve and a safety valve, the mixing device mixes a fuel flowing in from a fuel inlet and air flowing in from an air inlet to form a fuel-air mixture, the fan is for intake of the fuel and the air through the mixing device, the main flow regulator limits a mass flow of the fuel into the mixing device, the control valve, arranged upstream of the main flow regulator, controls a mass flow of the fuel into the mixing device, the safety valve, arranged upstream of the control valve, interrupts the mass flow of the fuel, the method comprising:

• detecting a differential pressure between a pressure at a measuring point upstream of the main flow regulator and downstream of the control valve and a reference pressure (p0, p1) at a reference measuring point;
• transmitting the differential pressure to an electronic evaluation system;
• comparing the differential pressure during a pre-purge phase where the safety valve is closed with the differential pressure after the pre-purge phase;
• and
• detecting an error by the comparison;
• the error is a non-existent or unconnected sensor and/or a poor or non-existent connection of the sensor to the measuring point and/or the reference measuring point,
• detecting a pressure difference between the pressure (p2) at the measuring point, which is located upstream of the main flow regulator and downstream of the control valve, and a reference pressure (p0, p1) at a reference measuring point;
• and
• recognizing, via the electronic evaluation system, the sensor as not present or not connected and/or as having a poor or non-existent connection to the measuring point and/or the reference measuring point if the differential pressure is outside a predetermined tolerance range.