What a Flame Sensor Is and Why It Matters

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

This time it’s your heat exchanger, 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 feature on your gas furnace. During the ignition cycle, your gas furnace goes through a process where either a spark or a hot surface igniter actually ignites the gas. As the gas is ignited, the flame sensor produces a current of electricity. The current is measured in micro amps. If the furnace’s control board doesn’t read the proper 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 impede the flame sensor’s ability to operate properly, which can end up causing the heating system to malfunction.

The way to determine if an unclean flame sensor is causing a furnace malfunction is to take a micro amp draw reading, which an expert furnace technician can supply you. If a dirty flame sensor is the guilty party, the technician will clean the sensor with steel wool. If dirt was the sole factor, we will see a significantly higher amp reading. If the reading does not change, the technician will carry on with the heating system repair diagnostic process.

If you aren’t sure your heating system 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 provide you with a full furnace maintenance or a no-charge in-home estimate on a new furnace.

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