What a Flame Sensor Is and Why It Matters

Receiving your routine furnace maintenance helps keep your furnace operating up to 30% more efficient and helps extend the life of your system. But things may still go wrong, 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 board. Now your find out the flame sensor has to be replaced.

By the way – what is a flame sensor?

A flame sensor is an important safety component on your gas furnace. During the ignition sequence, your gas furnace undergoes a process where either a spark or a hot surface igniter will actually ignite the gas. Once 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 does not read the proper level of micro amps, the furnace will quit giving the system fuel to stop an explosion.

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

The way to diagnose if an unclean 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 culprit, the furnace expert will clean the sensor with steel wool. If dirt was the sole factor, we will see a notably higher amp reading. If the reading does not change, the technician will carry on with the heating equipment 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 provide you with a full furnace maintenance or a free in-home estimate on a new heating system.

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