What a Flame Sensor Is and Why It Matters

Scheduling your routine furnace maintenance helps keep your heating equipment working up to thirty percent more efficient and helps extend the life of the equipment. But things may still malfunction, 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 control valve. Now your find out the flame sensor has to be replaced. 

What is a flame sensor, anyway? 

A flame sensor is a crucial safety feature on your gas furnace. During the ignition pattern, your gas furnace goes through a process where either a spark or a hot surface igniter will actually ignite the gas. As the gas is ignited, the flame sensor generates a current of electricity. This is measured in micro amps. If the furnace’s control board does not read the proper 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 hinder 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 causing a furnace malfunction is to take a micro amp draw reading, which a professional furnace technician can give you. If a dirty flame sensor is the offender, the heating expert will clean the sensor with steel wool. If dirt was the single factor, we will see a much higher amp reading. If the reading doesn’t change, the technician will continue with the heating equipment repair diagnostic process. 

If you aren’t sure your heating system is going to outlast these last few weeks of winter, give Service Experts Heating & 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.