What a Flame Sensor Is and Why It Matters

Scheduling your annual furnace maintenance helps keep your heating equipment operating up to thirty percent more efficient and helps extend the life of your furnace. But things may still stop working, and when they do, you might feel like you’re always hearing about something else. 

This time it’s your motor, next time it’s your pressure switch. Now your find out the flame sensor has to be replaced. 

Also, what is a flame sensor? 

A flame sensor is a crucial safety feature on your gas heating equipment. During the ignition cycle, your gas furnace undergoes a process where a spark or a hot surface ignitor actually ignites the gas. Once the gas is ignited, the flame sensor produces a current of electricity. The current is calculated in micro amps. If the furnace’s control board doesn’t read the proper 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 impede the flame sensor’s ability to operate properly, which can result in a malfunction of the furnace. 

The way to diagnose if an unclean flame sensor is the reason for a furnace malfunction is to take a micro amp draw reading, which a professional furnace technician can provide you. If a dirty flame sensor is the guilty party, the technician will clean the sensor with steel wool. If dirt was the sole factor, we will see a much higher amp reading. If the reading does not change, the technician will proceed with the heating equipment repair diagnostic process. 

If you aren’t sure your heating equipment is going to survivie these last few weeks of winter, give Stevenson Service Experts a call and we’ll come out and provide you with a full furnace maintenance or a complimentary in-home estimate on a new furnace.