Where is the flame sensor in a furnace?
The furnace’s flame sensor is located in front of the burners. It is a rod that sticks out where the flame comes out of the burner. The flame sensor is always on the opposite side of the ignitor. For example, if the ignitor is on the right side of the burners, then the flame sensor is on the left side.
What does a flame sensor do on a gas furnace?
A flame sensor is a crucial safety component on your gas heating system. During the ignition cycle, your gas furnace goes through a process where a spark or a hot surface ignitor will actually ignite the gas. As the gas is ignited, the flame sensor creates a current of electricity.
Do all gas furnaces have flame sensors?
Not all furnaces have a flame sensor, but if your furnace has one, it will be mounted close to the burner with the metal rod positioned in the flame. Flame sensors vary in size (2 to 4 inches) and shape (see examples below).
How much does flame sensor cost?
Flame Sensor It stops your furnace from letting off large amounts of natural gas if it’s not working properly. If the sensor is bad, it won’t be able to sense heat and will turn the furnace off. The average cost to repair or replace a flame sensor is between $75–$200.
What happens if flame sensor goes bad?
If your flame sensor is dirty or faulty, it will automatically shut down the heating unit if it doesn’t detect a flame. Most furnaces will go into a safety ignition lockout when a shutdown happens three times.
How do you know if furnace sensor is bad?
Furnace turns on and off down very quickly (after 2- 30 seconds). This is the classic symptom of a bad flame sensor. A faulty sensor doesn’t detect the heat that turning on a furnace makes, and subsequently closes the gas valve, shutting down the furnace. We see this as furnace short cycling in a few seconds.
Can I clean a flame sensor?
Clean the Sensor Once you have removed the sensor, gently rub the metal rod (and nothing else) with a very light grit sandpaper. Remember, you’re not sanding down an auto body here, just ridding the sensor of any buildup. Then, use a clean paper towel to wipe clean any dust left behind by the sanding.