What a Flame Sensor Is and Why It Matters

Scheduling your annual furnace maintenance helps keep your heating system running up to thirty 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 motor, next time it’s your pressure switch. Now you have to have your flame sensor replaced.

By the way – what is a flame sensor?

A flame sensor is a critical safety feature on your gas furnace. During the ignition cycle, your gas furnace goes through a process where either a spark or a hot surface igniter actually ignites the gas. Once the gas is ignited, the flame sensor creates a current of electricity. The electricity is measured in micro amps. If the furnace’s control board fails to read the proper 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 hinder the flame sensor’s ability to function properly, which can end up causing the heating system to malfunction.

The way to diagnose if an unclean flame sensor is to blame 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 guilty party, 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 shows no change, the technician will continue with the furnace repair diagnostic process.

If you aren’t certain your heating system is going to make it through these last few weeks of winter, give Service Experts Heating & Air Conditioning 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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