What a Flame Sensor Is and Why It Matters

February 26, 2017

Scheduling your annual furnace maintenance helps keep your furnace operating up to 30 percent more efficient and helps extend the life of your system. But things could still go wrong, and when they do, you may feel like there is always something else.

This time it’s your heat exchanger, next time it’s your pressure switch. Now your find out the flame sensor has to be replaced.

By the way – what is a flame sensor?

A flame sensor is a crucial safety feature on your gas heating equipment. During the ignition pattern, 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. The electricity is measured in micro amps. If the furnace’s control board doesn’t read the proper level of micro amps, the furnace will quit giving the system fuel to stop an explosion.

Over time, if the flame sensor is not adequately cleaned, oxidation or carbon buildup can hinder the flame sensor’s ability to work properly, which can cause the furnace to malfunction.

The way to determine if a dirty flame sensor is causing a furnace malfunction is to take a micro amp draw reading, which an expert furnace technician can provide you. If a dirty flame sensor is the culprit, the furnace expert will clean the sensor with steel wool. If dirt was the only factor, we will see a notably higher amp reading. If the reading shows no change, the technician will continue with the heating equipment repair diagnostic process.

If you aren’t sure your heating equipment is going to outlast these last few weeks of winter, give Becht/Givens Service Experts a call and we’ll come out and perform a full furnace maintenance or a complimentary in-home estimate on a new heating system.

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