What a Flame Sensor Is and Why It Matters

Setting up 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 could still go wrong, and when they do, you could feel like it’s always something else.

This time it’s your blower, next time it’s your pressure switch. Now you need to replace your flame sensor.

What is a flame sensor, anyway?

A flame sensor is a critical safety component on your gas heating equipment. During the ignition sequence, your gas furnace enters a process where either a spark or a hot surface igniter will actually ignite the gas. When the gas is ignited, the flame sensor produces a current of electricity. This is measured in micro amps. If the furnace’s control board does not read the right level of micro amps, the furnace will stop giving 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 determine if a soiled flame sensor is the reason for a furnace malfunction is to take a micro amp draw reading, which an expert furnace technician can supply you. If a dirty flame sensor is the reason, the technician will clean the sensor with steel wool. If dirt was the single factor, we will see a much higher amp reading. If the reading shows no change, the technician will proceed with the heating equipment repair diagnostic process.

If you aren’t confident your heating equipment is going to survivie these last few weeks of winter, give Epperson 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 furnace.

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