What a Flame Sensor Is and Why It Matters

Scheduling your seasonal furnace maintenance helps keep your heating equipment running up to 30% more efficient and helps extend the life of the equipment. But things may still stop working, and when they do, you might feel like there is always something else. 

This time it’s your heat exchanger, next time it’s your pressure switch. Now you have to have your flame sensor replaced. 

Also, what is a flame sensor? 

A flame sensor is an important safety feature on your gas furnace. During the ignition sequence, your gas furnace undergoes a process where either a spark or a hot surface igniter will ignite the gas. Once the gas is ignited, the flame sensor creates a current of electricity. This is calculated in micro amps. If the furnace’s control board does not 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 properly, oxidation or carbon buildup can interfere with the flame sensor’s ability to work properly, which can end up causing the heating system to malfunction. 

The way to determine 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 give you. If a dirty flame sensor is the reason, the technician will clean the sensor with steel wool. If dirt was the single factor, we will see a significantly higher amp reading. If the reading doesn’t change, the technician will proceed with the heating system repair diagnostic process. 

If you aren’t confident your heating equipment is going to outlast these last few weeks of winter, give Bryant Heating & Cooling Service Experts a call and we’ll come out and give you a full furnace maintenance or a free in-home estimate on a new heating system.