A boiler ignitor is a portion of a boiler that changes the fuel that is being fed into the machine into heat by lighting a connected burner. In older boiler models, ignitors were typically pilot lights that provided the initial fire that ignited the gas from the boiler's burners.
As of 2015, modern boilers or furnaces generally use hot electric surfaces as an ignitor. Expert opinion deems the new ignition system boilers to be more efficient, as well as more cost efficient since they do not use a constant stream of fuel like a pilot light. The electric ignitor creates heat through the usage of an electrical signal to initiate a spark.