What a Flame Sensor Is and Why It Matters

February 26, 2017

Setting up your seasonal furnace maintenance helps keep your furnace operating 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 it’s 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 a crucial safety feature on your gas heating equipment. During the ignition sequence, your gas furnace enters a process where either a hot surface ignitor or a spark will ignite the gas. Once the gas is ignited, the flame sensor creates a current of electricity. This is calculated in micro amps. If the furnace’s control board fails to read the proper level of micro amps, the furnace will quit 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 function 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 a professional furnace technician can give you. If a dirty flame sensor is the offender, 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 continue with the furnace repair diagnostic process.

If you aren’t sure your heating system is going to survivie these last few weeks of winter, give Parker Pearce Service Experts Heating & Air Conditioning a call and we’ll come out and perform a full furnace maintenance or a no-charge in-home estimate on a new furnace.

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