When the push button is depressed of a Gas Flame Failures Device the gas flows to the pilot burner, but the internal flow interrupter prevents passage of gas to the main burner. The pilot is lit and the push button held depressed until the thermocouple generates sufficient current to hold the main valve open (this may take up to 30 seconds). On release of the push button, gas is able to pass to the main appliance burner and is ignited by the pilot flame. Should the pilot be extinguished for any reason, the valve will shut down when the thermocouple cools and the current generated falls below the holding threshold (delay may be up to 60 seconds). No gas can flow again until the lighting operation is repeated.
All valves require connection to a pilot assembly and or thermocouple to provide flame supervision