What a Flame Sensor Is and Why It Matters

February 26, 2017

Setting up your routine furnace maintenance helps keep your heating equipment working up to 30% more efficient and helps extend the life of the equipment. But things can still malfunction, and when they do, you may feel like there is always something else.

This time it’s your blower, next time it’s your control valve. Now your find out the flame sensor has to be replaced.

What is a flame sensor, anyway?

A flame sensor is a critical safety component on your gas heating equipment. During the ignition pattern, your gas furnace undergoes a process where a spark or a hot surface ignitor will ignite 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 doesn’t read the proper level of micro amps, the furnace will stop giving the system fuel to avoid an explosion.

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

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 heating technician can give you. If a dirty flame sensor is the reason, 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 shows no change, the technician will proceed with the heating equipment repair diagnostic process.

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

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