What a Flame Sensor Is and Why It Matters

February 26, 2017

Receiving your seasonal furnace maintenance helps keep your furnace working up to 30% more efficient and helps extend the life of the equipment. But things could still malfunction, and when they do, you might feel like there is always something else.

This time it’s your heat exchanger, next time it’s your control valve. Now you need to replace your flame sensor.

By the way – what is a flame sensor?

A flame sensor is a critical safety feature on your gas heating system. During the ignition pattern, your gas furnace enters a process where a spark or a hot surface ignitor will actually ignite the gas. Once the gas is ignited, the flame sensor generates a current of electricity. This is quantified 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 appropriately, oxidation or carbon buildup can interfere with 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 causing 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 offender, 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 does not change, the technician will proceed with the heating system repair diagnostic process.

If you aren’t confident your heating equipment is going to make it through these last few weeks of winter, give Coastal Service Experts a call and we’ll come out and provide you with a full furnace maintenance or a complimentary in-home estimate on a new heating system.

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