What a Flame Sensor Is and Why It Matters

Setting up your annual furnace maintenance helps keep your heating system running up to thirty percent more efficient and helps extend the life of the equipment. But things could still malfunction, 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 control valve. Now your find out the flame sensor has to be replaced.

What is a flame sensor, anyway?

A flame sensor is a crucial safety component on your gas furnace. During the ignition pattern, your gas furnace undergoes 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 electricity is calculated in micro amps. If the furnace’s control board fails to read the right level of micro amps, the furnace will stop giving the system fuel to avoid an explosion.

Over time, if the flame sensor is not cleaned properly, oxidation or carbon buildup can restrict the flame sensor’s ability to function properly, which can end up causing the heating system to malfunction.

The way to establish if a soiled 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 offender, the furnace expert will clean the sensor with steel wool. If dirt was the only factor, we will see a much higher amp reading. If the reading shows no change, the technician will proceed with the furnace repair diagnostic process.

If you aren’t certain your furnace is going to survivie these last few weeks of winter, give Service Experts Heating & Air Conditioning a call and we’ll come out and give you a full furnace maintenance or a free in-home estimate on a new HVAC system.