What a Flame Sensor Is and Why It Matters

Setting up your routine furnace maintenance helps keep your heating system operating up to 30% more efficient and helps extend the life of your system. But things may 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 pressure switch. Now you need to replace your flame sensor.

What is a flame sensor, anyway?

A flame sensor is a crucial safety element on your gas heating equipment. During the ignition sequence, your gas furnace undergoes a process where either a spark or a hot surface igniter will actually ignite the gas. When the gas is ignited, the flame sensor creates a current of electricity. The electricity is calculated in micro amps. If the furnace’s control board fails to read the correct level of micro amps, the furnace will stop giving the system fuel to prevent 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 function properly, which can cause the furnace to malfunction.

The way to determine if an unclean flame sensor is the reason 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 guilty party, the heating expert will clean the sensor with steel wool. If dirt was the only factor, we will see a significantly higher amp reading. If the reading doesn’t 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 give you a full furnace maintenance or a complimentary in-home estimate on a new HVAC system.

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