What a Flame Sensor Is and Why It Matters

February 26, 2017

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

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

Also, what is a flame sensor?

A flame sensor is an important safety component on your gas heating system. During the ignition pattern, your gas furnace undergoes a process where a spark or a hot surface ignitor will actually ignite the gas. As the gas is ignited, the flame sensor generates a current of electricity. This is quantified 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 interfere with the flame sensor’s ability to function properly, which can result in a malfunction of the furnace.

The way to determine if an unclean flame sensor is to blame for a furnace malfunction is to take a micro amp draw reading, which a professional furnace technician can supply you. If a dirty flame sensor is the reason, the technician 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 furnace repair diagnostic process.

If you aren’t certain your furnace is going to make it through these last few weeks of winter, give Roland J. Down Service Experts Heating & Air Conditioning a call and we’ll come out and perform a full furnace maintenance or a free in-home estimate on a new heating system.

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