What a Flame Sensor Is and Why It Matters

Setting up your annual furnace maintenance helps keep your furnace working up to 30 percent more efficient and helps extend the life of your furnace. But things can still malfunction, and when they do, you may feel like you’re always hearing about something else.

This time it’s your motor, next time it’s your pressure switch. Now you need to replace your flame sensor.

What is a flame sensor, anyway?

A flame sensor is a crucial safety element on your gas heating equipment. During the ignition cycle, your gas furnace goes through a process where a spark or a hot surface ignitor will actually ignite the gas. Once the gas is ignited, the flame sensor creates a current of electricity. The electricity is quantified in micro amps. If the furnace’s control board does not read the proper 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 appropriately, oxidation or carbon buildup can impede the flame sensor’s ability to operate properly, which can end up causing the heating system to malfunction.

The way to diagnose if an unclean 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 sole factor, we will see a significantly higher amp reading. If the reading does not change, the technician will continue with the heating system repair diagnostic process.

If you aren’t certain your heating system is going to outlast these last few weeks of winter, give Strand Brothers Service Experts 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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