What a Flame Sensor Is and Why It Matters

February 26, 2017

Receiving your annual furnace maintenance helps keep your heating system working up to 30% more efficient and helps extend the life of the equipment. But things can still malfunction, 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 valve. Now you have to have your flame sensor replaced.

Also, what is a flame sensor?

A flame sensor is a critical safety element on your gas heating system. During the ignition cycle, your gas furnace enters a process where either a spark or a hot surface igniter actually ignites the gas. When 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 proper level of micro amps, the furnace will stop giving 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 operate properly, which can end up causing the heating system to malfunction.

The way to diagnose if a dirty flame sensor is the reason 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 offender, the furnace expert will clean the sensor with steel wool. If dirt was the single factor, we will see a notably 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 heating system is going to survivie these last few weeks of winter, give 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 heating system.

Contact Us