Abstract: A gas burner control system utilizes an electrical resistance igniter to ignite a main burner. Electronic sensing means is located adjacent the burner and adjacent a portion of the igniter where opposite voltage polarity exists between the igniter and sensing means. Current flows from the igniter to the sensing means when the igniter is heated above ignition temperature. Circuit means is responsive to such current flow to de-energize the igniter and enable gas to flow for a timed trial ignition period, the igniter having sufficient mass to remain at or above ignition temperature for the trial ignition period. When ignition occurs, the circuit means is responsive to current flow through burner flame from the sensing means to the burner to maintain gas flow.

Abstract: Safety ignition means for burner installations having a solenoid of a solenoid operated valve connected to a power source through a normally opened relay switch. The relay switch has a hold coil connected to the power source and a make coil connected to the power source through a flame switch which operates, when the flame switch is heated by the flame of the pilot burner, to energize a solenoid of a solenoid operated valve for main burner and de-energize the make coil. A normally closed bimetal switch is connected between a power supply and the safety ignition means and has a heat source connected in series with the make coil. If the pilot burner is not ignited for a predetermined period of time, the heat source heats the bimetal switch so that the bimetal switch is opened to separate the ignition means from the power supply.

Abstract: A control system for a gas burner of a domestic hot water system has a normally closed gas valve for controlling the supply of gas to the burner, and an electric solenoid for actuating the valve when energized by current of a first predetermined value. The solenoid can be held open by a current of a second predetermined value lower than the first. The solenoid current is derived from a mains a.c. supply through two thermistors in series. One of these thermistors has a negative temperature coefficient of resistance and provides a short delay to the operation of the solenoid when heat is initially demanded. The second thermistor, having a positive temperature coefficient of resistance, controls the valve lift time, that is to say, the limited time during which gas is supplied to the burner for enabling an attempt to ignite the burner to be made. The valve lift time is automatically reduced if the system is still hot from a previous operation, thereby preventing a possible explosion hazard.

Abstract: The safety control system is adapted for use in connection with a gas-fired infrared radiant heater which employs a pilot for ignition thereof. The system will cause the supply of gas to be discontinued to both the heater and pilot after a suitable time interval in the event that ignition of the pilot does not occur.

Abstract: A self-checking fuel ignition system of the pilot ignition type including a sampling flame sensor which effects periodic testing of the operability of a spark generating circuit to provide ignition sparks, and an energizing circuit which operates independently of the spark generating circuit but under the control of the flame sensor, to control the operation of fuel valves of the system and to effect the shut down of the system for loss of flame or ignition spark.

Abstract: Automatic electrical control systems for gas fired equipment. The systems embody electrical ignition. The systems eliminate the need for a constantly burning pilot. In one form, wherein the main burner is electrically ignited the pilot is omitted altogether. The systems are adapted to retrofit of existing systems having a pilot to provide for electrical ignition, eliminating constant burning of the pilot. Safety interlocks are embodied and responsive to a thermocouple, providing an assured safe and positive operation under all possible conditions.