What a Flame Sensor Is and Why It Matters

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

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

Also, what is a flame sensor?

A flame sensor is a crucial safety component on your gas furnace. During the ignition sequence, your gas furnace undergoes a process where either a hot surface ignitor or a spark actually ignites the gas. As the gas is ignited, the flame sensor creates a current of electricity. The current is calculated in micro amps. If the furnace’s control board does not read the correct level of micro amps, the furnace will no longer give the system fuel to avoid 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 operate properly, which can result in a malfunction of the furnace.

The way to determine if an unclean flame sensor is the reason 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 offender, the technician will clean the sensor with steel wool. If dirt was the single factor, we will see a much higher amp reading. If the reading doesn’t change, the technician will proceed with the furnace repair diagnostic process.

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

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