What a Flame Sensor Is and Why It Matters

February 26, 2017

Receiving your seasonal furnace maintenance helps keep your heating system running up to 30 percent more efficient and helps extend the life of your system. But things could still stop working, and when they do, you may feel like it’s always something else.

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

Also, what is a flame sensor?

A flame sensor is an important safety element on your gas furnace. During the ignition cycle, your gas furnace enters a process where either a spark or a hot surface igniter will ignite the gas. As the gas is ignited, the flame sensor produces a current of electricity. The electricity is calculated in micro amps. If the furnace’s control board does not read the right level of micro amps, the furnace will no longer give the system fuel to prevent an explosion.

Over time, if the flame sensor is not adequately cleaned, oxidation or carbon buildup can hinder the flame sensor’s ability to operate properly, which can end up causing the heating system to malfunction.

The way to establish 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 reason, the technician 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 system repair diagnostic process.

If you aren’t confident your furnace is going to survivie these last few weeks of winter, give Service Experts Heating & Air Conditioning a call and we’ll come out and perform a full furnace maintenance or a complimentary in-home estimate on a new HVAC system.

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