What a Flame Sensor Is and Why It Matters

Receiving your routine furnace maintenance helps keep your heating equipment operating up to 30% more efficient and helps extend the life of your furnace. But things could still malfunction, and when they do, you may feel like there is always something else.

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

What is a flame sensor, anyway?

A flame sensor is a critical safety component on your gas heating equipment. During the ignition pattern, your gas furnace undergoes a process where a spark or a hot surface ignitor will ignite the gas. As the gas is ignited, the flame sensor creates a current of electricity. This is calculated in micro amps. If the furnace’s control board fails to read the right 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 restrict the flame sensor’s ability to work properly, which can result in a malfunction of the furnace.

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 give you. If a dirty flame sensor is the reason, the heating expert will clean the sensor with steel wool. If dirt was the sole factor, we will see a significantly higher amp reading. If the reading shows no change, the technician will continue with the heating equipment repair diagnostic process.

If you aren’t certain your furnace is going to survivie these last few weeks of winter, give Midway Services a call and we’ll come out and perform a full furnace maintenance or a no-charge in-home estimate on a new furnace.