What a Flame Sensor Is and Why It Matters

Scheduling your seasonal furnace maintenance helps keep your furnace operating 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 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.

By the way – what is a flame sensor?

A flame sensor is a crucial safety component on your gas heating system. During the ignition cycle, your gas furnace goes through a process where a spark or a hot surface ignitor 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 does not read the proper level of micro amps, the furnace will no longer give the system fuel to avoid an explosion.

Over time, if the flame sensor is not cleaned properly, oxidation or carbon buildup can restrict the flame sensor’s ability to work properly, which can result in a malfunction of the furnace.

The way to establish if an unclean flame sensor is causing a furnace malfunction is to take a micro amp draw reading, which an expert heating technician can give you. If a dirty flame sensor is the guilty party, the heating 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 shows no change, the technician will carry on with the heating system repair diagnostic process.

If you aren’t certain your furnace is going to outlast 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 no-charge in-home estimate on a new furnace.

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