What a Flame Sensor Is and Why It Matters

February 26, 2017

Scheduling your annual furnace maintenance helps keep your heating equipment working up to 30 percent more efficient and helps extend the life of the equipment. But things could still stop working, and when they do, you may feel like there is always something else.

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

By the way – what is a flame sensor?

A flame sensor is a crucial safety feature on your gas furnace. During the ignition cycle, your gas furnace undergoes a process where either a spark or a hot surface igniter will actually ignite the gas. As the gas is ignited, the flame sensor creates a current of electricity. The electricity is calculated in micro amps. If the furnace’s control board doesn’t read the right 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 impede the flame sensor’s ability to work properly, which can result in a malfunction of the furnace.

The way to diagnose if a soiled flame sensor is causing a furnace malfunction is to take a micro amp draw reading, which a professional furnace technician can give you. If a dirty flame sensor is the reason, the furnace expert will clean the sensor with steel wool. If dirt was the single factor, we will see a significantly higher amp reading. If the reading does not change, the technician will proceed with the heating system repair diagnostic process.

If you aren’t certain your heating equipment is going to make it through these last few weeks of winter, give Aramendia Plumbing, Heating and Air, A Service Experts Company a call and we’ll come out and give you a full furnace maintenance or a complimentary in-home estimate on a new HVAC system.

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