What a Flame Sensor Is and Why It Matters

February 26, 2017

Receiving your routine furnace maintenance helps keep your furnace running up to 30% more efficient and helps extend the life of your system. But things can still go wrong, 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 you have to have your flame sensor replaced.

By the way – what is a flame sensor?

A flame sensor is a critical safety element on your gas furnace. During the ignition pattern, your gas furnace enters a process where either a spark or a hot surface igniter actually ignites the gas. Once the gas is ignited, the flame sensor produces a current of electricity. The current is measured in micro amps. If the furnace’s control board does not read the correct level of micro amps, the furnace will no longer give the system fuel to avoid an explosion.

Over time, if the flame sensor is not adequately cleaned, 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 a dirty flame sensor is causing a furnace malfunction is to take a micro amp draw reading, which an expert heating technician can supply you. If a dirty flame sensor is the culprit, the technician 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 Strand Brothers Service Experts a call and we’ll come out and give you a full furnace maintenance or a complimentary in-home estimate on a new furnace.

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