What a Flame Sensor Is and Why It Matters

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

This time it’s your heat exchanger, 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 a critical safety feature on your gas heating equipment. During the ignition pattern, your gas furnace goes through a process where either a hot surface ignitor or a spark will ignite the gas. When the gas is ignited, the flame sensor creates a current of electricity. The electricity is calculated in micro amps. If the furnace’s control board does not read the correct 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 impede the flame sensor’s ability to function properly, which can result in a malfunction of the furnace.

The way to establish 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 reason, the furnace expert will clean the sensor with steel wool. If dirt was the sole factor, we will see a much higher amp reading. If the reading doesn’t change, the technician will proceed with the heating system repair diagnostic process.

If you aren’t sure your heating equipment is going to outlast these last few weeks of winter, give Orangutan Home Services a call and we’ll come out and perform a full furnace maintenance or a complimentary in-home estimate on a new HVAC system.


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