Your furnace might seem simple from the outside, but modern units contain numerous parts that aid in efficiency, reliability, and comfort. Each component needs to work together to ensure even and dependable heating for your home, but your furnace wouldn't do much without its burners. The burners control the flow of fuel into the combustion chamber, ultimately providing heat for your home.
Burner issues can stop your furnace cold, so it's a good idea to understand how these components work, why they fail, and what you can do to repair them or avoid issues in the future. Although there's plenty to understand about these seemingly straightforward parts, here are just three essential things you should know about how your burners work.
1. Your Furnace Probably Has Multiple Burners
Modern furnaces typically use assemblies that consist of multiple burner units. Each burner has a simple job: deliver an air/fuel mixture to the igniter to generate heat. Depending on your make and model of furnace, your burner assembly might be a single piece, or you may be able to replace each burner unit independently.
The actual number of burners in the furnace can vary. Higher capacity furnaces will generally have more burners, while units with lower BTU output will have fewer. Unless your furnace has a multi-stage furnace, all burners should always run at full power. If they don't, you have a problem that you'll need to address.
2. The Flames Don't Lie
Inspecting your flames is a relatively straightforward diagnostic step you can take any time you suspect a burner problem. Consult your owner's manual to determine how to remove your furnace door. The burner may also have a cover that you'll need to remove. Turn your furnace off while working near it, although you'll need to turn it back on when you're ready to test.
Once you can see the burners, turn your thermostat up so the furnace begins heating. You should observe each burner and see bright, blue, and steady flames. Flickering or orange flames indicate potential problems. Likewise, a burner that doesn't ignite at all may point to an issue with clogging, fuel flow, or airflow.
3. Complete Combustion Matters
Weak flames don't just mean that your furnace will burn cooler or less efficiently. Incomplete combustion creates extra soot and debris, which can further clog your burners or damage other components. In severe cases, poorly operating burners may fail to trigger the furnace's limit switch. In this case, you won't get any heat at all since the blower motor won't kick on.
While you can inspect your burners for trouble, you should rely on a professional to conduct heating repairs when you notice a problem. Many burner failures point to other issues with your furnace, and an expert can diagnose these problems to get your furnace producing consistent and reliable heat again.