What a Flame Sensor Is and Why It Matters Published on February 26, 2017 Setting up your seasonal furnace maintenance helps keep your furnace operating up to 30% more efficient and helps extend the life of your system. But things may still stop working, and when they do, you may feel like you’re always hearing about something else. This time it’s your motor, next time it’s your control board. Now you have to have your flame sensor replaced. Also, what is a flame sensor? A flame sensor is an important safety element on your gas heating system. During the ignition sequence, your gas furnace undergoes a process where either a spark or a hot surface igniter actually ignites the gas. When the gas is ignited, the flame sensor generates a current of electricity. The electricity is calculated in micro amps. If the furnace’s control board does not read the correct level of micro amps, the furnace will quit giving the system fuel to avoid an explosion. Over time, if the flame sensor is not cleaned appropriately, oxidation or carbon buildup can hinder the flame sensor’s ability to operate properly, which can result in a malfunction of the furnace. The way to establish if a soiled flame sensor is to blame for a furnace malfunction is to take a micro amp draw reading, which an expert heating technician can supply you. If a dirty flame sensor is the culprit, the heating expert will clean the sensor with steel wool. If dirt was the sole factor, we will see a much higher amp reading. If the reading doesn’t change, the technician will continue with the furnace repair diagnostic process. If you aren’t sure your heating equipment is going to outlast these last few weeks of winter, give Mountainwest Service Experts Heating & Air Conditioning a call and we’ll come out and perform a full furnace maintenance or a complimentary in-home estimate on a new furnace.