What a Flame Sensor Is and Why It Matters

Receiving your seasonal furnace maintenance helps keep your furnace operating up to 30 percent more efficient and helps extend the life of your system. But things can still stop working, and when they do, you might feel like you’re always hearing about something else.

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

Also, what is a flame sensor?

A flame sensor is an important safety feature on your gas heating system. During the ignition sequence, your gas furnace enters a process where either a hot surface ignitor or a spark will ignite the gas. As the gas is ignited, the flame sensor produces a current of electricity. The electricity is calculated in micro amps. If the furnace’s control board fails to read the right level of micro amps, the furnace will stop giving the system fuel to prevent an explosion.

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

The way to establish 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 provide you. If a dirty flame sensor is the reason, 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 continue with the furnace repair diagnostic process.

If you aren’t sure your furnace is going to make it through these last few weeks of winter, give 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 HVAC system.

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