What a Flame Sensor Is and Why It Matters

Receiving your routine furnace maintenance helps keep your furnace working up to 30% more efficient and helps extend the life of your furnace. 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 heat exchanger, next time it’s your control board. Now you need to replace your flame sensor.

Also, what is a flame sensor?

A flame sensor is a crucial safety component on your gas heating equipment. During the ignition cycle, your gas furnace goes through a process where either a spark or a hot surface igniter actually ignites the gas. When the gas is ignited, the flame sensor generates a current of electricity. The current is measured in micro amps. If the furnace’s control board fails to read the correct level of micro amps, the furnace will quit giving the system fuel to stop 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 the reason for 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 single factor, we will see a significantly higher amp reading. If the reading doesn’t change, the technician will continue with the furnace repair diagnostic process.

If you aren’t confident your heating equipment is going to outlast these last few weeks of winter, give 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 furnace.