What a Flame Sensor Is and Why It Matters

Receiving your annual furnace maintenance helps keep your heating system working up to 30% more efficient and helps extend the life of the equipment. But things could still malfunction, and when they do, you could 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 pattern, your gas furnace goes through a process where either a spark or a hot surface igniter actually ignites the gas. When the gas is ignited, the flame sensor produces a current of electricity. This is measured in micro amps. If the furnace’s control board does not read the correct level of micro amps, the furnace will stop giving the system fuel to prevent an explosion. 

Over time, if the flame sensor is not adequately cleaned, oxidation or carbon buildup can interfere with the flame sensor’s ability to operate properly, which can cause the furnace 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 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 significantly 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 furnace is going to make it through these last few weeks of winter, give Golden Seal Service Experts a call and we’ll come out and give you a full furnace maintenance or a free in-home estimate on a new furnace. 

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