What a Flame Sensor Is and Why It Matters

Scheduling your routine furnace maintenance helps keep your heating system working up to 30% more efficient and helps extend the life of the equipment. But things can still go wrong, and when they do, you might feel like there is always something else.

This time it’s your motor, next time it’s your pressure switch. Now you need to replace your flame sensor.

Also, what is a flame sensor?

A flame sensor is a crucial safety feature 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 will ignite the gas. When 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 doesn’t read the proper level of micro amps, the furnace will no longer give the system fuel to prevent an explosion.

Over time, if the flame sensor is not cleaned properly, oxidation or carbon buildup can interfere with the flame sensor’s ability to function properly, which can result in a malfunction of the furnace.

The way to establish if a soiled flame sensor is to blame for a furnace malfunction is to take a micro amp draw reading, which an expert furnace technician can give you. If a dirty flame sensor is the culprit, the heating 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 does not change, the technician will carry on with the furnace repair diagnostic process.

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

Contact Us