What a Flame Sensor Is and Why It Matters

Setting up your annual furnace maintenance helps keep your heating system running up to 30% more efficient and helps extend the life of the equipment. But things could still stop working, and when they do, you might feel like you’re always hearing about something else.

This time it’s your blower, next time it’s your pressure switch. Now you have to have your flame sensor replaced.

By the way – what is a flame sensor?

A flame sensor is a critical safety feature on your gas heating equipment. During the ignition sequence, your gas furnace enters a process where either a spark or a hot surface igniter will actually 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 fails to 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 interfere with the flame sensor’s ability to work properly, which can end up causing the heating system to malfunction.

The way to determine 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 provide 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 carry on with the heating system repair diagnostic process.

If you aren’t confident your heating equipment is going to outlast these last few weeks of winter, give Peitz 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 heating system.