What a Flame Sensor Is and Why It Matters

Setting up your routine furnace maintenance helps keep your heating system operating up to thirty percent more efficient and helps extend the life of your furnace. But things could still stop working, and when they do, you may feel like there is always something else.

This time it’s your heat exchanger, next time it’s your pressure switch. Now your find out the flame sensor has to be replaced.

By the way – what is a flame sensor?

A flame sensor is a critical safety element on your gas furnace. During the ignition sequence, your gas furnace enters a process where either a spark or a hot surface igniter will actually ignite the gas. When the gas is ignited, the flame sensor generates a current of electricity. The current is quantified in micro amps. If the furnace’s control board doesn’t read the right level of micro amps, the furnace will no longer give the system fuel to prevent an explosion.

Over time, if the flame sensor is not adequately cleaned, oxidation or carbon buildup can hinder the flame sensor’s ability to operate 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 give you. If a dirty flame sensor is the reason, the heating expert will clean the sensor with steel wool. If dirt was the sole factor, we will see a much higher amp reading. If the reading doesn’t change, the technician will carry on with the furnace repair diagnostic process.

If you aren’t sure your heating equipment is going to make it through 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 no-charge in-home estimate on a new heating system.