What a Flame Sensor Is and Why It Matters

Setting up your annual furnace maintenance helps keep your furnace operating up to 30 percent more efficient and helps extend the life of your furnace. But things could still malfunction, 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.

Also, what is a flame sensor?

A flame sensor is a crucial safety component on your gas heating system. During the ignition pattern, your gas furnace goes through 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 quantified in micro amps. If the furnace’s control board fails to read the proper level of micro amps, the furnace will quit giving the system fuel to prevent 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 cause the furnace to malfunction.

The way to determine if an unclean flame sensor is causing a furnace malfunction is to take a micro amp draw reading, which a professional furnace technician can supply you. If a dirty flame sensor is the guilty party, the furnace expert will clean the sensor with steel wool. If dirt was the only factor, we will see a notably 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 Roland J. Down Service Experts a call and we’ll come out and perform a full furnace maintenance or a free in-home estimate on a new heating system.

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