You will need to replace the thermocouple or flame sensor, which ever this has. You can also try to use really fine sand paper and rub the soot off the sensor and try that. Some times that does in fact work. If not you will have to replace it. A thermocouple can be purchased at lowes and a flame sensor can be purchased online at ebay.com <- The cheapest place for flame sensors, just make sure you get the proper one. Hope this helps you.