What a Flame Sensor Is and Why It Matters

February 26, 2017

Scheduling your routine furnace maintenance helps keep your heating system running up to 30% more efficient and helps extend the life of the equipment. But things could still go wrong, and when they do, you might feel like there is always something else.

This time it’s your motor, next time it’s your control board. 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 undergoes a process where a spark or a hot surface ignitor will ignite the gas. As the gas is ignited, the flame sensor produces 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 hinder the flame sensor’s ability to function properly, which can result in a malfunction of the furnace.

The way to diagnose if a dirty 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 offender, the heating expert will clean the sensor with steel wool. If dirt was the only factor, we will see a notably higher amp reading. If the reading doesn’t change, the technician will continue with the heating equipment repair diagnostic process.

If you aren’t sure your heating system is going to make it through these last few weeks of winter, give Church Services a call and we’ll come out and perform a full furnace maintenance or a no-charge in-home estimate on a new HVAC system.

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