Abstract: Improved automatic ignition system (10) for gas fired devices such as boilers, clothes dryers, ranges, and the like. The system (10) is of the type including a variable resistance ignition means (16) having a particular temperature characteristic disposed in proximity to the burner (14) for igniting gas flowing therethrough when the ignition means (16) is energized. The improved system includes detection means (12) for repeatedly measuring the resistance of the ignition means (16) and for comparing such measurements, and activating means (12) for activating the gas valve opening means (56) to open the valve (60) when the detection means (12) establishes that the ignition means (16) is in the portion of its temperature characteristic where the temperature thereof is sufficient to ignite gas.

Abstract: An intermittent pulsing ignition system for gas fired devices includes a pulser assembly having a predetermined on/off cycle, providing full wave alternating current during the on cycle and half wave current during the off cycle, to an electrical ignition element. The full wave current is sufficient to heat the ignition element to the ignition temperature of the gas and the half wave current permits the ignition element to cool during the off cycle thereby prolonging its useful life.