What a Flame Sensor Is and Why It Matters

Scheduling your annual furnace maintenance helps keep your heating system operating up to 30% more efficient and helps extend the life of your furnace. But things may 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 valve. Now you need to replace your flame sensor. 

Also, what is a flame sensor? 

A flame sensor is a critical safety component on your gas heating equipment. During the ignition pattern, your gas furnace enters a process where a spark or a hot surface ignitor will actually ignite the gas. As the gas is ignited, the flame sensor creates a current of electricity. The current is measured in micro amps. If the furnace’s control board doesn’t read the correct level of micro amps, the furnace will no longer give the system fuel to stop an explosion. 

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

The way to diagnose if a soiled flame sensor is to blame for a furnace malfunction is to take a micro amp draw reading, which a professional furnace technician can provide you. If a dirty flame sensor is the guilty party, the furnace expert will clean the sensor with steel wool. If dirt was the only factor, we will see a notably higher amp reading. If the reading doesn’t change, the technician will proceed with the heating system repair diagnostic process. 

If you aren’t sure your heating system is going to outlast these last few weeks of winter, give Stallion Heating and Air Conditioning a call and we’ll come out and give you a full furnace maintenance or a complimentary in-home estimate on a new HVAC system.