What a Flame Sensor Is and Why It Matters

Setting up your routine furnace maintenance helps keep your heating equipment working up to thirty percent more efficient and helps extend the life of your furnace. But things can still go wrong, and when they do, you may feel like you’re always hearing about something else.

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

Also, what is a flame sensor?

A flame sensor is an important safety feature on your gas furnace. During the ignition sequence, your gas furnace goes through a process where either a spark or a hot surface igniter will actually ignite the gas. When the gas is ignited, the flame sensor generates a current of electricity. This is quantified in micro amps. If the furnace’s control board doesn’t read the right 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 appropriately, oxidation or carbon buildup can hinder 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 a professional furnace technician can supply you. If a dirty flame sensor is the offender, the technician will clean the sensor with steel wool. If dirt was the single factor, we will see a much higher amp reading. If the reading does not change, the technician will carry on with the heating equipment repair diagnostic process.

If you aren’t certain your furnace 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 give you a full furnace maintenance or a no-charge in-home estimate on a new furnace.