What a Flame Sensor Is and Why It Matters

February 26, 2017

Receiving your annual furnace maintenance helps keep your furnace running up to 30% more efficient and helps extend the life of your system. But things can still go wrong, and when they do, you might feel like there is always something else.

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

Also, what is a flame sensor?

A flame sensor is a critical safety element on your gas furnace. During the ignition pattern, your gas furnace enters a process where either a spark or a hot surface igniter actually ignites the gas. As the gas is ignited, the flame sensor produces a current of electricity. This 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 hinder the flame sensor’s ability to work 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 an expert furnace technician can supply you. If a dirty flame sensor is the guilty party, 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 proceed with the heating equipment repair diagnostic process.

If you aren’t certain your furnace is going to make it through these last few weeks of winter, give Jack Nelson Service Experts Heating & Air Conditioning a call and we’ll come out and provide you with a full furnace maintenance or a complimentary in-home estimate on a new furnace.

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