What a Flame Sensor Is and Why It Matters

February 26, 2017

Scheduling your routine furnace maintenance helps keep your furnace running up to 30 percent 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 blower, next time it’s your pressure switch. Now your find out the flame sensor has to be replaced.

Also, what is a flame sensor?

A flame sensor is a critical safety feature on your gas furnace. During the ignition sequence, your gas furnace goes through a process where a spark or a hot surface ignitor will ignite the gas. Once the gas is ignited, the flame sensor generates a current of electricity. This is calculated in micro amps. If the furnace’s control board does not read the proper 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 properly, oxidation or carbon buildup can impede the flame sensor’s ability to work properly, which can end up causing the heating system to malfunction.

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

If you aren’t sure your heating equipment is going to make it through these last few weeks of winter, give Climate Control Service Experts Heating & Air Conditioning a call and we’ll come out and give you a full furnace maintenance or a free in-home estimate on a new furnace.

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