What a Flame Sensor Is and Why It Matters

February 26, 2017

Scheduling your annual 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 you’re always hearing about something else.

This time it’s your blower, next time it’s your pressure switch. Now you need to replace your flame sensor.

What is a flame sensor, anyway?

A flame sensor is a critical safety feature on your gas furnace. During the ignition pattern, your gas furnace undergoes a process where either a hot surface ignitor or a spark will ignite the gas. As the gas is ignited, the flame sensor creates a current of electricity. This is calculated in micro amps. If the furnace’s control board does not 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 appropriately, oxidation or carbon buildup can hinder the flame sensor’s ability to work properly, which can result in a malfunction of the furnace.

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 an expert 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 significantly higher amp reading. If the reading doesn’t change, the technician will continue with the heating system repair diagnostic process.

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

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