What a Flame Sensor Is and Why It Matters

February 26, 2017

Scheduling your routine furnace maintenance helps keep your heating system working up to 30% more efficient and helps extend the life of the equipment. But things may still stop working, and when they do, you might feel like there is always something else.

This time it’s your motor, next time it’s your control valve. Now your find out the flame sensor has to be replaced.

What is a flame sensor, anyway?

A flame sensor is a crucial safety feature on your gas heating equipment. During the ignition sequence, your gas furnace goes through a process where a spark or a hot surface ignitor will ignite the gas. When the gas is ignited, the flame sensor creates a current of electricity. The electricity is calculated in micro amps. If the furnace’s control board fails to read the right level of micro amps, the furnace will quit giving the system fuel to stop an explosion.

Over time, if the flame sensor is not cleaned properly, oxidation or carbon buildup can impede the flame sensor’s ability to function properly, which can cause the furnace to malfunction.

The way to diagnose if a dirty flame sensor is the reason for a furnace malfunction is to take a micro amp draw reading, which an expert furnace technician can provide you. If a dirty flame sensor is the culprit, the furnace expert will clean the sensor with steel wool. If dirt was the single factor, we will see a significantly higher amp reading. If the reading doesn’t change, the technician will continue with the furnace repair diagnostic process.

If you aren’t certain your heating system is going to outlast these last few weeks of winter, give Comfort Masters Service Experts Heating & Air Conditioning a call and we’ll come out and provide you with a full furnace maintenance or a no-charge in-home estimate on a new furnace.

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