What a Flame Sensor Is and Why It Matters

Scheduling your seasonal furnace maintenance helps keep your furnace running 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 might 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.

What is a flame sensor, anyway?

A flame sensor is an important 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. When the gas is ignited, the flame sensor generates a current of electricity. The electricity is calculated 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 restrict the flame sensor’s ability to function properly, which can result in a malfunction of the furnace.

The way to diagnose if an unclean flame sensor is causing a furnace malfunction is to take a micro amp draw reading, which a professional 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 sole 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 confident 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 free in-home estimate on a new furnace.

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