What a Flame Sensor Is and Why It Matters

Setting up your routine furnace maintenance helps keep your heating system running up to 30% more efficient and helps extend the life of your furnace. But things can still stop working, and when they do, you might feel like it’s always something else.

This time it’s your heat exchanger, next time it’s your control board. Now your find out the flame sensor has to be replaced.

What is a flame sensor, anyway?

A flame sensor is a crucial safety feature on your gas furnace. During the ignition pattern, your gas furnace goes through a process where a spark or a hot surface ignitor actually ignites the gas. When 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 prevent an explosion.

Over time, if the flame sensor is not cleaned properly, oxidation or carbon buildup can restrict the flame sensor’s ability to function properly, which can end up causing the heating system to malfunction.

The way to establish if a dirty 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 offender, the furnace expert will clean the sensor with steel wool. If dirt was the sole factor, we will see a notably higher amp reading. If the reading doesn’t change, the technician will continue with the heating equipment repair diagnostic process.

If you aren’t certain your heating system is going to make it through these last few weeks of winter, give Wesley Wood 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 heating system.