What a Flame Sensor Is and Why It Matters

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

This time it’s your motor, 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 furnace. During the ignition cycle, your gas furnace undergoes a process where either a hot surface ignitor or a spark will actually ignite the gas. Once the gas is ignited, the flame sensor produces a current of electricity. The current is calculated in micro amps. If the furnace’s control board does not read the right level of micro amps, the furnace will quit giving the system fuel to prevent an explosion. 

Over time, if the flame sensor is not adequately cleaned, oxidation or carbon buildup can interfere with the flame sensor’s ability to function properly, which can cause the furnace to malfunction. 

The way to diagnose if an unclean flame sensor is to blame for a furnace malfunction is to take a micro amp draw reading, which an expert heating technician can provide you. If a dirty flame sensor is the reason, the heating expert will clean the sensor with steel wool. If dirt was the single factor, we will see a much higher amp reading. If the reading shows no change, the technician will continue with the furnace repair diagnostic process. 

If you aren’t confident your heating system is going to make it through these last few weeks of winter, give Winnipeg Supply Service Experts a call and we’ll come out and perform a full furnace maintenance or a no-charge in-home estimate on a new furnace.