A system for verifying operation of a contact includes a voltage source connected to a first terminal of the contact through a first switch; a second switch connected to a second terminal of the contact; a third switch connected to the second terminal of the contact; a voltage output connected to the second switch and the third switch; and a controller to compare the voltage output to a first voltage and a second voltage; wherein the voltage output indicates operation of the contact in response to status of the first switch, the switch and the third switch.

A system for checking high fluid pressure and low fluid pressure limit switches for valves and fluid supply to a fluid consumption appliance. The system may incorporate one or more pressure sensors at a fluid valve to detect an amount of fluid pressure. The one or more pressure sensors may be connected to a processor. The high fluid pressure and low fluid pressure sensor limit switches may also be connecter to the processor. A display and user control may be connected to the processor.

A method for controlling the operation of a burner, the burner including a control board with a first control unit and a first memory, which stores first values of operating parameters of the burner, and a display device, which displays one or more items of data relating to the functioning of the burner, the display device including a second memory, which stores second values of operating parameters of the burner, each first and second operating parameters being capable of being changed over time. The method includes setting for each operating parameter at least one first value in the first memory, and at least one second value in the second memory; comparing, for each operating parameter, a corresponding first value and second value; if the first value and the second value are different, changing one of the first or second values, so that the first and second values are the same.

A gas regulating unit (10) for fail-safe regulation of a gas, specifically in a gas heater (1) or a gas burner, has a communication interface (15), a first sensor assembly (11), and a second sensor assembly (12). The first sensor assembly (11) is configured to acquire measured values from which a signed first differential pressure (p11) between a process pressure (p1) of the gas and a reference pressure (p0) is determinable. The second sensor assembly (12) is configured to acquire measured values from which a signed second differential pressure (p12) between the reference pressure (p0) and the process pressure (p1) is determinable. Thus, the signed first differential pressure (p11) and the signed second differential pressure (p12) are signed mutually inverse differential pressures (p11, p12). The communication interface (15) is configured to send the mutually inverse differential pressures (p11, p12) and/or the measured values to an external receiver.

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.

Various embodiments include a combustion apparatus comprising: a control facility for open- and/or closed-loop control of the apparatus; a combustion chamber; an actuator adjusting an air supply; and a combustion sensor in a region of a flame of the chamber. The control facility stores a list of support points. A first air supply value is assigned to each support point. A drift test value and an index for ascertainment of a test result are assigned to each support point. The controller: generates a specified air supply; selects a support point as a function of the air supply; and decides on a test result using the index for the support point. To ascertain a test result: receives a signal from the combustion sensor; determines a new test result; ascertains a changed drift test value for the selected support point; and stores the changed drift test value as the drift test value.