What a Flame Sensor Is and Why It Matters

Scheduling your seasonal furnace maintenance helps keep your heating system running up to thirty percent more efficient and helps extend the life of your furnace. But things can still stop working, and when they do, you might feel like you’re always hearing about something else.

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

What is a flame sensor, anyway?

A flame sensor is a crucial safety component on your gas heating equipment. During the ignition cycle, your gas furnace enters a process where a spark or a hot surface ignitor actually ignites the gas. Once the gas is ignited, the flame sensor creates a current of electricity. The electricity is quantified in micro amps. If the furnace’s control board fails to read the right level of micro amps, the furnace will stop giving the system fuel to stop an explosion.

Over time, if the flame sensor is not cleaned properly, oxidation or carbon buildup can interfere with the flame sensor’s ability to function 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 furnace technician can give you. If a dirty flame sensor is the culprit, the heating expert will clean the sensor with steel wool. If dirt was the sole factor, we will see a much higher amp reading. If the reading doesn’t change, the technician will proceed 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 McElroy Service Experts a call and we’ll come out and give you a full furnace maintenance or a free in-home estimate on a new heating system.

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