What a Flame Sensor Is and Why It Matters

February 26, 2017

Scheduling your annual furnace maintenance helps keep your furnace working up to 30 percent more efficient and helps extend the life of your system. But things can still malfunction, and when they do, you might feel like it’s always something else.

This time it’s your blower, next time it’s your control board. Now you have to have your flame sensor replaced.

By the way – what is a flame sensor?

A flame sensor is an important safety component on your gas heating system. During the ignition cycle, your gas furnace undergoes a process where either a spark or a hot surface igniter will ignite the gas. When the gas is ignited, the flame sensor creates a current of electricity. This is quantified in micro amps. If the furnace’s control board does not read the right level of micro amps, the furnace will quit giving the system fuel to avoid an explosion.

Over time, if the flame sensor is not adequately cleaned, oxidation or carbon buildup can restrict the flame sensor’s ability to function properly, which can result in a malfunction of the furnace.

The way to establish if a dirty flame sensor is to blame for 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 guilty party, the furnace expert will clean the sensor with steel wool. If dirt was the sole factor, we will see a significantly higher amp reading. If the reading does not change, the technician will proceed with the heating system repair diagnostic process.

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

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