What a Flame Sensor Is and Why It Matters

February 26, 2017

Receiving your routine 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 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 you have to have your flame sensor replaced.

What is a flame sensor, anyway?

A flame sensor is a crucial safety component on your gas heating system. During the ignition cycle, your gas furnace enters a process where either a hot surface ignitor or a spark actually ignites the gas. As the gas is ignited, the flame sensor creates a current of electricity. The current is quantified in micro amps. If the furnace’s control board fails to read the proper level of micro amps, the furnace will no longer give the system fuel to stop an explosion.

Over time, if the flame sensor is not cleaned appropriately, oxidation or carbon buildup can restrict the flame sensor’s ability to work properly, which can result in a malfunction of the furnace.

The way to establish 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 system repair diagnostic process.

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

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