What a Flame Sensor Is and Why It Matters

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

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

What is a flame sensor, anyway?

A flame sensor is a critical safety feature 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. When the gas is ignited, the flame sensor produces a current of electricity. The current is calculated in micro amps. If the furnace’s control board fails to read the correct 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 hinder the flame sensor’s ability to function properly, which can end up causing the heating system to malfunction.

The way to establish if an unclean 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 furnace expert 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 continue with the heating equipment repair diagnostic process.

If you aren’t certain your heating system is going to make it through these last few weeks of winter, give Strand Brothers Service Experts a call and we’ll come out and provide you with a full furnace maintenance or a complimentary in-home estimate on a new furnace.