Hot Surface Ignition is an alternative method to standing pilots or spark ignition systems for igniting gas. The theory is that a surface has a great deal more area than a flame or especially a spark which should
make for reliable ignition of the gas. This type of igniter is composed of materials like silicon carbide or silicon nitride which have large resistance values to electrical flow. When subjected to electrical flow
(typically 120 volts) the surface will heat up to temperatures hotter than the ignition temperature of the gas. Hot surface igniters are very brittle so use caution when working around them. Do not touch the surface
of a Hot Surface Igniter as oils from the skin will cause hot spots and shorten the life of the igniter. The Hot Surface Ignition control opens the circuit to the HSI igniter once flame has been proven. The Hot
Surface Igniter is a good example of why flame or spark is not required to ignite a flammable gas. The combustion triangle below contains the word "heat" not spark or flame.
