Quality and value for money; Made of durable and wear-resistant metal, free of harmful chemicals for increased efficiency and longevity. Save time and money by not having to spend a fortune to fix your furnace. Fix Symptom: Furnace does not heat. Detects the presence of a flame, and if the sensor does not detect a flame, it will shut off the gas valve, preventing unprocessed gas from dumping into your home. This is a brand new upgraded Furnace Flame Sensor