What a Flame Sensor Is and Why It Matters

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

This time it’s your motor, 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 element on your gas heating equipment. During the ignition cycle, your gas furnace undergoes a process where a spark or a hot surface ignitor actually ignites the gas. As the gas is ignited, the flame sensor produces a current of electricity. The current is calculated in micro amps. If the furnace’s control board does not 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 appropriately, 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 diagnose if a dirty flame sensor is to blame for a furnace malfunction is to take a micro amp draw reading, which an expert heating technician can supply you. If a dirty flame sensor is the guilty party, the heating expert will clean the sensor with steel wool. If dirt was the single factor, we will see a significantly higher amp reading. If the reading does not change, the technician will proceed with the furnace repair diagnostic process.

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

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