What a Flame Sensor Is and Why It Matters

February 26, 2017

Setting up your annual furnace maintenance helps keep your furnace running up to thirty percent more efficient and helps extend the life of your system. But things may still stop working, and when they do, you could 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 crucial safety component on your gas heating system. During the ignition sequence, your gas furnace undergoes a process where either a spark or a hot surface igniter will ignite the gas. As the gas is ignited, the flame sensor creates a current of electricity. This is quantified in micro amps. If the furnace’s control board fails to read the right level of micro amps, the furnace will stop giving the system fuel to avoid an explosion.

Over time, if the flame sensor is not adequately cleaned, oxidation or carbon buildup can impede the flame sensor’s ability to operate 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 an expert furnace technician can supply you. If a dirty flame sensor is the reason, the furnace expert will clean the sensor with steel wool. If dirt was the only 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 furnace is going to survivie these last few weeks of winter, give Rob's Albertan Service Experts 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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