What a Flame Sensor Is and Why It Matters

February 26, 2017

Scheduling your annual furnace maintenance helps keep your heating equipment operating up to 30% more efficient and helps extend the life of the equipment. But things could still go wrong, and when they do, you could feel like it’s always something else.

This time it’s your blower, next time it’s your control valve. Now your find out the flame sensor has to be replaced.

Also, what is a flame sensor?

A flame sensor is an important safety component on your gas heating equipment. During the ignition cycle, your gas furnace goes through a process where either a spark or a hot surface igniter will ignite the gas. When the gas is ignited, the flame sensor generates a current of electricity. The electricity is quantified in micro amps. If the furnace’s control board fails to read the proper level of micro amps, the furnace will quit giving the system fuel to prevent 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 function properly, which can end up causing the heating system to malfunction.

The way to determine if a soiled flame sensor is the reason 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 offender, the technician 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 furnace repair diagnostic process.

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

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