What a Flame Sensor Is and Why It Matters

Setting up your seasonal furnace maintenance helps keep your furnace operating up to 30 percent more efficient and helps extend the life of your furnace. But things can still go wrong, and when they do, you could feel like you’re always hearing about something else.

This time it’s your motor, next time it’s your control board. Now you need to replace your flame sensor.

What is a flame sensor, anyway?

A flame sensor is an important safety element on your gas heating system. During the ignition pattern, your gas furnace goes through a process where either a spark or a hot surface igniter actually ignites the gas. As the gas is ignited, the flame sensor generates a current of electricity. This is measured in micro amps. If the furnace’s control board does not read the correct level of micro amps, the furnace will no longer give the system fuel to stop 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 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 offender, 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 continue with the heating equipment repair diagnostic process.

If you aren’t confident your heating equipment is going to make it through these last few weeks of winter, give Pardee 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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