What a Flame Sensor Is and Why It Matters

Receiving your seasonal furnace maintenance helps keep your heating system working up to 30% more efficient and helps extend the life of your furnace. But things can still go wrong, 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 board. Now you need to replace your flame sensor.

By the way – what is a flame sensor?

A flame sensor is a critical safety element on your gas heating system. During the ignition pattern, your gas furnace enters a process where a spark or a hot surface ignitor actually ignites the gas. Once the gas is ignited, the flame sensor creates a current of electricity. This is quantified in micro amps. If the furnace’s control board does not read the right level of micro amps, the furnace will stop giving the system fuel to prevent an explosion.

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

The way to establish if an unclean flame sensor is to blame 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 technician will clean the sensor with steel wool. If dirt was the sole factor, we will see a much higher amp reading. If the reading doesn’t change, the technician will proceed with the furnace repair diagnostic process.

If you aren’t confident your heating equipment is going to survivie these last few weeks of winter, give Coastal Service Experts a call and we’ll come out and give you a full furnace maintenance or a complimentary in-home estimate on a new heating system.