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Why is My Pilot Light Flame Yellow Instead of Blue?

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small_4271395441Although homes with newer furnaces most likely use electronic ignitions, there are still many homes in the St. Louis area with older systems that use a conventional standing pilot light. Owners of these systems should be aware of a common issue that will prevent their furnaces from working properly and could potentially be a safety hazard: a pilot light that’s burning yellow. Today we’re going to talk about why your pilot light might start to burn yellow, what effects it can have and how you can fix the problem!


Pilot lights should burn blue


When your furnace is functioning normally, the pilot light should burn a deep blue color. This is the natural color of a flame that is receiving an adequate amount of oxygen. When the amount of oxygen to a pilot light is restricted, it becomes a “lazy” flame and burns yellow instead of blue.


The most common reason why a pilot light would start to burn yellow is that the air intake valve to the pilot light is clogged with dirt. When this happens, air will be blocked to the flame and it will suffer from incomplete combustion (causing the yellow color). If there is a small amount of dirt blocking the air, the yellow color might only be at the tip of the flame. If there is a large amount of dirt, the entire flame will burn yellow.


What happens when your pilot light burns yellow?


There are two main issues with a pilot light burning yellow. The first issue is that the pilot light will frequently go out and need to be relit. This happens because yellow flames do not burn as hot as blue flames. Because of this, the yellow flame will not adequately heat up the thermocouple, and the gas supply to the pilot light will be shut off.


Another issue with a yellow-burning pilot light is that it allows carbon monoxide to leak into your home’s air. That’s because carbon monoxide is not completely burned up by the lazy flame, and the excess gas will simply escape.


How can you stop your pilot light from burning yellow instead of blue?


If you notice that you pilot light is burning yellow instead of blue, contact Jerry Kelly. The issue can typically be fixed by cleaning out the air intake valve to the pilot light, which should only be done by a professional who knows how to access and repair the part.


If you have any questions about these signs that your furnace needs repair, or if you’d like a heating system serviced or installed in your home, contact Jerry Kelly, your St. Louis furnace installation and repair contractor. We provide service all over the St. Louis area, including towns like St. Paul St. Peters and Town and Country, MO.


photo credit: pursanovd via photopin cc


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