What a Flame Sensor Is and Why It Matters

February 26, 2017

Scheduling your seasonal furnace maintenance helps keep your furnace running up to 30 percent more efficient and helps extend the life of your system. But things could still go wrong, and when they do, you may feel like you’re always hearing about something else.

This time it’s your motor, next time it’s your control valve. Now you have to have your flame sensor replaced.

Also, what is a flame sensor?

A flame sensor is an important safety feature on your gas heating equipment. During the ignition sequence, your gas furnace enters a process where either a spark or a hot surface igniter will 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 does not read the right 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 cleaned properly, oxidation or carbon buildup can interfere with the flame sensor’s ability to work properly, which can end up causing the heating system to malfunction.

The way to establish if a soiled 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 guilty party, 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 shows no change, the technician will carry on with the heating equipment repair diagnostic process.

If you aren’t certain your heating equipment is going to make it through these last few weeks of winter, give Roy Inch & Sons Service Experts Heating & Air Conditioning a call and we’ll come out and perform a full furnace maintenance or a no-charge in-home estimate on a new heating system.

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