Hot surface ignitors are found on most modern furnaces to light the gas flames when the units start up. Electricity passes through the Silicon Carbide or the newer Silicon Nitride ignitor and makes it glow red hot. Operating under normal conditions a hot surface ignitor will last for 3 to 5 years. Eventually they crack and need to be replaced, similar to a light bulb.
The Honeywell Glow Fly hot surface igniter is a popular model available at www.supplyhouse.com. It is made with the newest Silicon Nitride technology and the Q3200U1004 Glow Fly kit comes with mounting brackets and detailed installation instructions.
