How Do You Test A Flame Sensor?
To test a flame sensor, turn off the power to the furnace and remove the sensor. Use a multi-meter to measure the sensor’s resistance. If the resistance is within the manufacturer’s recommended range, the sensor is functioning properly. If the resistance falls outside of the recommended range, the sensor should be replaced. Additionally, the sensor should be checked for any physical damage or build-up of debris or soot, which could affect its performance.