What a Flame Sensor Is and Why It Matters

Setting up your routine furnace maintenance helps keep your heating system operating up to thirty percent more efficient and helps extend the life of your system. But things may still malfunction, and when they do, you could feel like there is always something else.

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

By the way – what is a flame sensor?

A flame sensor is a critical safety feature on your gas heating system. During the ignition pattern, your gas furnace enters a process where either a spark or a hot surface igniter will ignite the gas. When the gas is ignited, the flame sensor generates a current of electricity. This is measured 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 appropriately, oxidation or carbon buildup can restrict the flame sensor’s ability to function properly, which can cause the furnace to malfunction.

The way to establish if an unclean flame sensor is the reason for 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 guilty party, the technician will clean the sensor with steel wool. If dirt was the only 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 confident 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 give you a full furnace maintenance or a free in-home estimate on a new HVAC system.

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