What a Flame Sensor Is and Why It Matters

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

This time it’s your motor, next time it’s your control board. Now you have to have your flame sensor replaced.

By the way – what is a flame sensor?

A flame sensor is an important safety element on your gas furnace. During the ignition pattern, your gas furnace undergoes a process where either a spark or a hot surface igniter will ignite the gas. When the gas is ignited, the flame sensor creates a current of electricity. The electricity is quantified in micro amps. If the furnace’s control board fails to read the right 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 cause the furnace to malfunction.

The way to determine if a dirty flame sensor is causing 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 reason, the furnace expert will clean the sensor with steel wool. If dirt was the only factor, we will see a much higher amp reading. If the reading shows no change, the technician will carry on with the heating system repair diagnostic process.

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

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