What a Flame Sensor Is and Why It Matters

Receiving your seasonal furnace maintenance helps keep your heating equipment operating up to 30 percent more efficient and helps extend the life of the equipment. But things can still go wrong, and when they do, you might feel like it’s always something else. 

This time it’s your heat exchanger, next time it’s your pressure switch. Now your find out the flame sensor has to be replaced. 

Also, what is a flame sensor? 

A flame sensor is a crucial safety component on your gas heating system. During the ignition sequence, your gas furnace undergoes a process where a spark or a hot surface ignitor actually ignites the gas. When the gas is ignited, the flame sensor creates a current of electricity. This 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 avoid an explosion. 

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

The way to diagnose if a soiled flame sensor is the reason 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 offender, the technician 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 carry on with the heating system repair diagnostic process. 

If you aren’t sure your heating equipment is going to survivie these last few weeks of winter, give Stevenson Service Experts a call and we’ll come out and provide you with a full furnace maintenance or a no-charge in-home estimate on a new heating system.