What a Flame Sensor Is and Why It Matters

February 26, 2017

Setting up your annual furnace maintenance helps keep your furnace operating up to 30 percent more efficient and helps extend the life of the equipment. But things can still go wrong, and when they do, you could feel like it’s always something else.

This time it’s your motor, next time it’s your control valve. 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 undergoes a process where either a hot surface ignitor or a spark actually ignites the gas. As the gas is ignited, the flame sensor creates a current of electricity. This is calculated in micro amps. If the furnace’s control board does not read the right level of micro amps, the furnace will stop giving the system fuel to stop an explosion.

Over time, if the flame sensor is not adequately cleaned, oxidation or carbon buildup can impede the flame sensor’s ability to work properly, which can end up causing the heating system to malfunction.

The way to determine if a dirty flame sensor is causing 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 heating expert will clean the sensor with steel wool. If dirt was the only factor, we will see a much higher amp reading. If the reading does not change, the technician will proceed with the heating equipment repair diagnostic process.

If you aren’t sure your heating equipment is going to survivie these last few weeks of winter, give Pardee Service Experts Heating & Air Conditioning a call and we’ll come out and perform a full furnace maintenance or a free in-home estimate on a new heating system.

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