What a Flame Sensor Is and Why It Matters

February 26, 2017

Receiving your seasonal furnace maintenance helps keep your furnace operating up to 30% more efficient and helps extend the life of your system. But things can still stop working, and when they do, you may feel like you’re always hearing about something else.

This time it’s your blower, next time it’s your pressure switch. Now you have to have your flame sensor replaced.

What is a flame sensor, anyway?

A flame sensor is an important safety element on your gas heating equipment. During the ignition pattern, your gas furnace enters a process where either a spark or a hot surface igniter will ignite the gas. As the gas is ignited, the flame sensor generates a current of electricity. The current is quantified 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 stop an explosion.

Over time, if the flame sensor is not adequately cleaned, 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 establish if a dirty flame sensor is to blame for a furnace malfunction is to take a micro amp draw reading, which a professional 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 single factor, we will see a much higher amp reading. If the reading doesn’t change, the technician will proceed with the heating system repair diagnostic process.

If you aren’t sure your heating equipment is going to outlast these last few weeks of winter, give Peachtree Service Experts Heating & Air Conditioning a call and we’ll come out and provide you with a full furnace maintenance or a no-charge in-home estimate on a new heating system.

Contact Us