What a Flame Sensor Is and Why It Matters

Setting up your seasonal furnace maintenance helps keep your furnace operating up to 30% more efficient and helps extend the life of your furnace. But things may still go wrong, and when they do, you might feel like there is always something else.

This time it’s your heat exchanger, next time it’s your control board. Now you need to replace your flame sensor.

By the way – what is a flame sensor?

A flame sensor is a crucial safety feature on your gas heating system. During the ignition cycle, your gas furnace enters a process where either a spark or a hot surface igniter will ignite the gas. Once the gas is ignited, the flame sensor generates a current of electricity. This is quantified in micro amps. If the furnace’s control board doesn’t 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 operate properly, which can cause the furnace to malfunction.

The way to establish if a soiled flame sensor is causing a furnace malfunction is to take a micro amp draw reading, which an expert heating 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 only factor, we will see a notably higher amp reading. If the reading does not change, the technician will carry on with the furnace repair diagnostic process.

If you aren’t certain your furnace is going to make it through these last few weeks of winter, give R & M Climate Control Service Experts a call and we’ll come out and give you a full furnace maintenance or a no-charge in-home estimate on a new furnace.

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