What Do You Know About a Furnace Flame Sensor and How It Works?

Furnace Flame Sensor

The flame sensor plays an important role in the safe operation of a gas furnace. Most newer furnaces don’t utilize the old-fashioned pilot light flame to ignite the gas burner. Instead, when the thermostat opens the main gas valve to the burner, the burner is lit by an electronic igniter. But suppose the furnace igniter fails and no flame is present, resulting in dangerous gas leakage into the house.

That’s where this critical sensor plays a part. It senses the burner flame and allows the gas valve to continue feeding gas to the burner. Conversely, if no burner flame is detected, the flow of gas is automatically shut off.

Sensing the Flame

The system works like this:

When Good Flame Sensors Go Bad

Over time, a furnace flame sensor may begin to generate false readings, causing the furnace to rapidly shut down after startup even though the burner flame is present. This may be due to a cracked or broken sensor rod, an electrical short, or a sensor that is dislodged and no longer contacts the burner flame. The most common cause is coating with carbon residue from the combustion process. A qualified HVAC technician can check voltage readings produced by the sensor and, if a problem exists, quickly replace the sensor or, in some cases, simply clean it to restore proper function.

For professional service to resolve flame-sensor issues, contact the heating experts at Jackson & Sons.

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When you need heating or air conditioning repairs, maintenance or system replacements, you need a company you can count on for dependability and quality service. Contact us at Jackson & Sons at 919-734-9611. Our professional team of technicians look forward to providing energy efficient and cost effective solutions to keep your home or business comfortable at all times.

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