What a Flame Sensor Is and Why It Matters

February 26, 2017

Setting up your seasonal furnace maintenance helps keep your heating system operating up to thirty percent more efficient and helps extend the life of your furnace. But things could still go wrong, 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 you need to replace your flame sensor.

What is a flame sensor, anyway?

A flame sensor is a critical safety component on your gas heating system. During the ignition pattern, your gas furnace enters a process where either a hot surface ignitor or a spark will actually 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 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 hinder the flame sensor’s ability to function properly, which can cause the furnace to malfunction.

The way to determine if an unclean flame sensor is the reason for 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 guilty party, the furnace expert will clean the sensor with steel wool. If dirt was the single factor, we will see a much higher amp reading. If the reading does not change, the technician will proceed with the heating system repair diagnostic process.

If you aren’t sure your furnace is going to make it through these last few weeks of winter, give Rolf Griffin 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 heating system.

Contact Us