What a Flame Sensor Is and Why It Matters

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

This time it’s your blower, next time it’s your pressure switch. Now your find out the flame sensor has to be replaced.

By the way – what is a flame sensor?

A flame sensor is a critical safety element on your gas furnace. During the ignition pattern, your gas furnace goes through a process where either a hot surface ignitor or a spark will ignite the gas. As the gas is ignited, the flame sensor generates a current of electricity. This is measured in micro amps. If the furnace’s control board does not read the correct 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 appropriately, oxidation or carbon buildup can restrict the flame sensor’s ability to work properly, which can cause the furnace to malfunction.

The way to establish if an unclean flame sensor is the reason for a furnace malfunction is to take a micro amp draw reading, which a professional furnace technician can give you. If a dirty flame sensor is the culprit, 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 does not change, the technician will continue with the furnace repair diagnostic process.

If you aren’t sure your furnace is going to outlast these last few weeks of winter, give Neal Harris Service Experts a call and we’ll come out and perform a full furnace maintenance or a complimentary in-home estimate on a new heating system.

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