What a Flame Sensor Is and Why It Matters

February 26, 2017

Setting up your routine furnace maintenance helps keep your heating system running up to 30% more efficient and helps extend the life of the equipment. But things can still stop working, and when they do, you might feel like it’s always something else.

This time it’s your motor, 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 a crucial safety element on your gas furnace. During the ignition pattern, your gas furnace goes through a process where a spark or a hot surface ignitor will actually 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 quit giving the system fuel to avoid 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 end up causing the heating system 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 give you. If a dirty flame sensor is the offender, 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 proceed with the heating equipment repair diagnostic process.

If you aren’t certain your heating system is going to survivie these last few weeks of winter, give Wesley Wood 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 furnace.

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