What a Flame Sensor Is and Why It Matters

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

This time it’s your heat exchanger, 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 an important safety component on your gas heating system. During the ignition cycle, your gas furnace enters a process where a spark or a hot surface ignitor will ignite the gas. Once the gas is ignited, the flame sensor generates 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 cleaned appropriately, oxidation or carbon buildup can impede the flame sensor’s ability to work properly, which can cause the furnace to malfunction.

The way to diagnose if a soiled flame sensor is to blame for a furnace malfunction is to take a micro amp draw reading, which an expert heating technician can give 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 doesn’t change, the technician will continue with the furnace repair diagnostic process.

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

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