What a Flame Sensor Is and Why It Matters

February 26, 2017

Scheduling your seasonal furnace maintenance helps keep your furnace operating up to 30% more efficient and helps extend the life of your furnace. But things could still stop working, and when they do, you might feel like you’re always hearing about 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 a crucial safety component on your gas heating equipment. During the ignition cycle, your gas furnace enters a process where a spark or a hot surface ignitor will actually ignite the gas. Once the gas is ignited, the flame sensor generates a current of electricity. The electricity is quantified 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 properly, oxidation or carbon buildup can interfere with the flame sensor’s ability to work properly, which can end up causing the heating system 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 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 doesn’t change, the technician will continue with the furnace repair diagnostic process.

If you aren’t sure your heating equipment is going to survivie these last few weeks of winter, give McElroy Service Experts Heating & Air Conditioning a call and we’ll come out and give you a full furnace maintenance or a complimentary in-home estimate on a new furnace.

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