What a Flame Sensor Is and Why It Matters

Scheduling your annual furnace maintenance helps keep your heating system running up to thirty percent more efficient and helps extend the life of your system. But things could still go wrong, and when they do, you might feel like you’re always hearing about something else. 

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

What is a flame sensor, anyway? 

A flame sensor is an important safety component on your gas furnace. During the ignition cycle, your gas furnace goes through a process where either a spark or a hot surface igniter will ignite the gas. When the gas is ignited, the flame sensor creates a current of electricity. This is calculated in micro amps. If the furnace’s control board fails to read the correct 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 determine if a soiled flame sensor is to blame 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 technician 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 proceed 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 Calverley Service Experts a call and we’ll come out and provide you with a full furnace maintenance or a free in-home estimate on a new furnace. 

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