What a Flame Sensor Is and Why It Matters

February 26, 2017

Scheduling your routine furnace maintenance helps keep your heating equipment working up to 30% more efficient and helps extend the life of your system. But things can still stop working, and when they do, you could 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. Once the gas is ignited, the flame sensor produces a current of electricity. The current is measured in micro amps. If the furnace’s control board does not read the correct level of micro amps, the furnace will quit 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 end up causing the heating system to malfunction.

The way to diagnose 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 give 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 notably higher amp reading. If the reading doesn’t change, the technician will continue with the furnace repair diagnostic process.

If you aren’t certain your heating equipment is going to outlast these last few weeks of winter, give Sunbeam Service Experts Heating & Air Conditioning a call and we’ll come out and perform a full furnace maintenance or a free in-home estimate on a new HVAC system.

Contact Us