What a Flame Sensor Is and Why It Matters

Setting up your annual furnace maintenance helps keep your heating equipment working up to 30% more efficient and helps extend the life of your system. But things could still stop working, and when they do, you could feel like you’re always hearing about something else.

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

By the way – what is a flame sensor?

A flame sensor is a critical safety element on your gas furnace. During the ignition cycle, your gas furnace undergoes a process where a spark or a hot surface ignitor actually ignites the gas. As the gas is ignited, the flame sensor creates a current of electricity. The current is calculated in micro amps. If the furnace’s control board doesn’t read the right 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 hinder the flame sensor’s ability to function properly, which can result in a malfunction of the furnace.

The way to determine if a dirty flame sensor is to blame for 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 offender, the furnace expert will clean the sensor with steel wool. If dirt was the only factor, we will see a significantly higher amp reading. If the reading does not change, the technician will continue with the heating equipment repair diagnostic process.

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

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