Abstract: A fail-safe, self-checking ignition and control system for a gas burning apparatus having a pilot burner which is initially ignited by electric ignition means upon a need for operation of the apparatus and which in turn ignites a main burner after a flame is established at the pilot burner, the gas flow to the pilot burner being through a first valve and the gas flow to the main burner being through a second valve receiving its gas supply from the first valve. Energization of the ignition means and the two valves is controlled by circuit means of the system including a time delay device, two relays, and solid state flame detecting means. Each time the system is initially energized upon a need for operation of the gas burning apparatus, it tests the critical components of the system and acts to prevent operation of the apparatus if the failure of any such critical component is detected.

Abstract: A control system for a gas burning apparatus having a pilot burner which is initially ignited by electric ignition means upon a need for operation of the apparatus and which in turn ignites a main burner after a flame is established at the pilot burner, the gas flow to the pilot burner being through a first valve and the gas flow to the main burner being through a second valve receiving its gas supply from the first valve. The control system includes flame relay switching means responsive to the presence and absence of flame at the pilot burner and actuated when the control system is initially energized to open the first valve while preventing opening of the second valve and to energize a holding circuit which maintains the first valve open and enables opening of the second valve when the flame relay switching means is subsequently deactuated in response to the establishment of a pilot flame.