A burner includes an atomizing chamber, a flame tube in front of the atomizing chamber adapted to direct combusting fuel introduced by the atomizing chamber along an interior of the flame tube, and a controller. The controller is programmed to independently control rate of fuel flow to the atomizing chamber, rate of atomizing air flow to the atomizing chamber, and rate of combustion air to the flame tub. The controller is also programmed to perform operations including regulating, based on output of a gas sensor, at least the rate of combustion air to the flame tube to substantially maintain a first predetermined amount of excess air in the flame tube.

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 premixing apparatus for mixing air with a fuel gas to supply a burner with an air-fuel mixture via a fan includes: a zero governor and a motor-driven type of variable throttle valve, both being disposed in a gas supply passage; and an excess air ratio detecting device for detecting an excess air ratio of the air-fuel mixture, thereby regulating an opening degree of the variable throttle valve so that the excess air ratio of the air-fuel mixture becomes a predetermined value. An arrangement is made to prevent an ignition failure from occurring in an attempt to perform an ignition operation in a state in which, due to a trouble with the variable throttle valve of remaining opened or remaining closed, the excess air ratio of the air-fuel mixture becomes too small or too excessive. The variable throttle valve is provided with a sensing device.

A current discharge probability of a flame sensor is calculated based on the number of drive pulses applied to the flame sensor and the number of discharges determined to have occurred in the flame sensor after receiving the drive pulses. Degradation indices (degradation progress and remaining lifetime) indicating the current degradation state of the flame sensor are calculated based on the calculated current discharge probability of the flame sensor.

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 flame rod analysis system, methods for determining a condition of a flame and a flame rod, and circuits for determining a condition of a flame and a flame rod. The flame rod analysis system comprises energy storage connectable to a flame rod, a pulsed source connected to the energy storage and providing a voltage pulse or a current pulse, and a buffer to allow a processor to measure a buffered voltage at various time points. Flame rod analysis systems can distinguish between various flame conditions (no flame, low flame, etc.) while simultaneously characterizing the condition of the flame rod (shorted to ground, contaminated, etc.). Some flame rod analysis systems can directly measure the resistance of the flame rod.

A low powered system for providing sufficient current to a fuel control mechanism drive. The system may have a fuel control mechanism pick circuit that has an energy storage mechanism for providing a large amount of current for a short time to the fuel control mechanism drive. A safety switch may be enabled with a special signal to let current flow to the fuel control mechanism drive to operate a corresponding fuel control mechanism for controlling fuel to a pilot light or heating element. The pilot light or heating element may provide heat to a thermoelectric source that generates electrical power from the heat. The electrical power may go to a single DC-to-DC converter and voltage clamp for providing a voltage source to a microcontroller and other circuits of the system. The pick circuit may prevent a harmful reverse flow of current from the storage mechanism to the thermoelectric source.

A method is disclosed for diagnosing a valve assembly having valve members serially arranged along a flow channel of the valve assembly connecting at least one inlet and at least one outlet of the valve assembly. All of the serially arranged valve members of the valve assembly are opended to allow fluid to flow through the flow channel. The flow of fluid through the flow channel is measured by at least one sensor. At least one of the valve members is openend, and at least one sensor checks for fluid leakage caused by at least one faulted valve member. The at least one sensor may include a flow sensor, e.g., a mass flow sensor.

A low powered system for providing sufficient current to a fuel control mechanism drive. The system may have a fuel control mechanism pick circuit that has an energy storage mechanism for providing a large amount of current for a short time to the fuel control mechanism drive. A safety switch may be enabled with a special signal to let current flow to the fuel control mechanism drive to operate a corresponding fuel control mechanism for controlling fuel to a pilot light or heating element. The pilot light or heating element may provide heat to a thermoelectric source that generates electrical power from the heat. The electrical power may go to a single DC-to-DC converter and voltage clamp for providing a voltage source to a microcontroller and other circuits of the system. The pick circuit may prevent a harmful reverse flow of current from the storage mechanism to the thermoelectric source.

A method for the safety-oriented control of at least one final control element of at least one electrically actuated gas valve, which is switched by means of two relays connected in series, wherein the final control element is activated only if the first relay and the second relay are tripped, wherein a flow of current over the first relay is monitored by a first monitoring device, a flow of current over the second relay is monitored by a second monitoring device, and a control device is programmed in such a way that the final control element is activated by tripping the two relays only if both the first monitoring device and the second monitoring device report to the control device that there is no flow of current before the activation.