The Ferroli Flame Sensing and Ignition Kit is based near the electrodes. Usually, there are two different types of electrodes: ignition electrodes and flame sensing electrodes. The ignition electrode creates the spark that begins the combustion procedure within the boiler The flame-sensing electrodes are responsible for monitoring whether there is a flame present in the burner. This is an important safety device that makes sure the boiler isn't still supplying gas without a flame.