What a Flame Sensor Is and Why It Matters

February 26, 2017

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

This time it’s your blower, next time it’s your control board. Now you need to replace your flame sensor.

By the way – what is a flame sensor?

A flame sensor is an important safety component on your gas heating equipment. During the ignition pattern, your gas furnace undergoes a process where either a spark or a hot surface igniter actually ignites the gas. As the gas is ignited, the flame sensor generates a current of electricity. The current is quantified in micro amps. If the furnace’s control board doesn’t read the correct level of micro amps, the furnace will no longer give the system fuel to stop 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 function 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 furnace technician can supply you. If a dirty flame sensor is the culprit, the technician will clean the sensor with steel wool. If dirt was the only factor, we will see a notably higher amp reading. If the reading shows no change, the technician will proceed with the heating system repair diagnostic process.

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

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