A standing pilot generator is the standard ignition device for most natural gas heating systems. It is the continuous flame at the bottom of the heater. The pilot light is responsible for starting the burners which generate heat.
The standing pilot generator has a basic design. A flame is started by a gas line terminating in a small burner. A bit of composite metal wire, a “thermocouple,” connects the burner to a valve in the gas line; then, the thermocouple registers the heat which generates an electric current when the pilot light is lit. The current travels down the thermocouple to the gas valve and opens it. This allows the pilot light to keep burning. The thermocouple’s electric current will stop when the pilot light goes out, and the gas valve will close; thus, This will prevent gas from flooding the home.