What a Flame Sensor Is and Why It Matters

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

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

Also, what is a flame sensor?

A flame sensor is an important safety element on your gas heating system. During the ignition cycle, your gas furnace undergoes a process where either a hot surface ignitor or a spark will actually ignite 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 doesn’t read the proper level of micro amps, the furnace will no longer give 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 a professional furnace technician can supply you. If a dirty flame sensor is the reason, 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 doesn’t change, the technician will carry on with the furnace repair diagnostic process.

If you aren’t sure your furnace 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 heating system.

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