What a Flame Sensor Is and Why It Matters

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

This time it’s your blower, 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 critical safety component on your gas heating equipment. During the ignition pattern, your gas furnace goes through a process where a spark or a hot surface ignitor will ignite the gas. As the gas is ignited, the flame sensor produces a current of electricity. This is quantified in micro amps. If the furnace’s control board doesn’t read the proper level of micro amps, the furnace will stop giving the system fuel to avoid 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 cause the furnace to malfunction.

The way to establish if a dirty flame sensor is the reason for a furnace malfunction is to take a micro amp draw reading, which an expert heating technician can give you. If a dirty flame sensor is the guilty party, the technician will clean the sensor with steel wool. If dirt was the sole factor, we will see a significantly higher amp reading. If the reading shows no change, the technician will proceed with the heating equipment repair diagnostic process.

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

Contact Us