What a Flame Sensor Is and Why It Matters

February 26, 2017

Scheduling your routine furnace maintenance helps keep your heating system working up to 30% more efficient and helps extend the life of your system. But things could still stop working, and when they do, you could feel like you’re always hearing about 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.

Also, what is a flame sensor?

A flame sensor is a critical safety feature on your gas heating equipment. During the ignition pattern, your gas furnace undergoes a process where either a spark or a hot surface igniter will actually ignite the gas. Once the gas is ignited, the flame sensor produces a current of electricity. This is measured in micro amps. If the furnace’s control board doesn’t read the correct level of micro amps, the furnace will no longer give the system fuel to prevent an explosion.

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

The way to determine if an unclean flame sensor is causing a furnace malfunction is to take a micro amp draw reading, which a professional furnace technician can provide 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 doesn’t change, the technician will continue with the heating system repair diagnostic process.

If you aren’t sure 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 perform a full furnace maintenance or a free in-home estimate on a new furnace.

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