What Causes a Yellow Flame in a Gas Furnace?
If you ever see a yellow flame in your furnace, call A1 Mechanical immediately. As the trusted providers of furnace repair in Dayton, Ohio, they know gas furnace issues require rapid response and expert attention. Keep reading to discover what a yellow flame means and what we can do about it.
The Role of a Pilot Light in a Gas Furnace
While most new gas furnaces don’t use a pilot light, an older model will still have one. When the thermostat detects the need for warmer air, it opens the gas valve, flooding the chamber with fuel. The pilot light ignites it and starts warming the air.
The flame should appear a natural blue, which indicates the right gas and air mixture. When the light starts turning yellow, it suggests a problem with combustion or other serious issues.
The Most Common Causes of a Yellow Flame
What are the most common reasons a flame turns yellow? HVAC specialists frequently see the following problems.
The Mixture May Have Too Much Air
Too much oxygen is the most common reason a pilot light turns yellow in a furnace or stove burner. However, the reason for the increased air varies. A certified technician can diagnose the exact nature of the problem.
Why is too much oxygen an issue? In most cases, it won’t threaten the home’s safety, but it causes a significant drop in efficiency. The property owner will see a substantial increase in monthly energy bills until they invest in repairs.
The Device May Have a Clogged Air Intake Valve
The air intake valve regulates how much oxygen enters the chamber and mixes with the gas. You may see a yellow flame in your furnace when it becomes loose or doesn’t close completely. The excessive amount of oxygen turns the flame yellow.
However, if the valve has buildup or can’t open, you’ll experience the opposite problem. The pilot light extinguishes, which allows the gas to enter back into the home.
Excessive Airflow Can Create a Flickering Flame
Too much oxygen becomes a problem when it involves a breeze or constant airflow. If the combustion chamber doesn’t have the proper sealing, it allows a slight wind to move through the furnace, and a flickering flame may snuff out.
If this happens frequently, the home has a higher risk of a gas leak. Stay vigilant for the smell of sulfur and take the following steps if you notice a problem:
- Immediately exit the house without using electronics like a phone or light switch.
- Call the utility company from a safe distance and ask them to shut off the gas supply.
- Contact an HVAC professional for emergency repairs.
- Find a place to spend time until experts resolve the problem.
The Combustion Process May Produce Too Many Byproducts
Homeowners have a more serious problem if the discolored flame arises from excessive byproducts of the combustion process. Burning gas always leads to the production of soot and carbon monoxide. A well-functioning system expels these materials through a flue to keep the home safe.
Blockages in the ventilation can prevent these substances from leaving the furnace. The yellow flame indicates higher concentration levels, but the carbon monoxide could leak into the home. If you have any gas appliances, install detectors in essential locations like bedrooms and the kitchen.
How Professionals Safely Address Gas Furnace Problems
How does a certified HVAC technician address combustion and airflow issues? They’ll take the following steps.
The Technician Starts With a Meticulous Cleaning
A thorough furnace cleaning often solves many issues because dirt buildup causes various problems with the heating system. For example, cleaning debris off the air intake valve can help it close completely and restore the appropriate gas-air mixture to the combustion process. If cleaning doesn’t resolve the yellow light, the technician moves to the next troubleshooting step.
The Professional Should Check the Thermocouple and Other Components
The thermocouple senses a flame and opens the gas valve. If it malfunctions, it may fail to detect the flame, and the chamber will have too much oxygen and not enough gas.
To ensure the quality of their work, the technician should also inspect other components like the ventilation system. They can adeptly repair or replace any components with issues.
They’ll Test for Carbon Monoxide and Gas Leaks
When they detect a yellow flame in a furnace, the expert should perform due diligence and test for toxic or hazardous substances in the home. If they find carbon monoxide or a gas leak, they’ll have a more detailed idea of the problem’s cause. In an emergency, they’ll ask you to exit the home until they can complete repairs.
The Process Concludes With Relighting the Light and Testing Their Work
After completing the necessary repairs, the HVAC contractor will reignite the pilot light. Even if it turns blue, they’ll test the system to ensure the problem doesn’t arise again. Never work with a company that doesn’t test their work.
They May Suggest Upgrading to a Newer Model
In older furnaces, repairs may not adequately address the problem or provide a long-term solution. If the professional thinks the aging heating system risks your safety, they’ll strongly encourage you to upgrade. This often provides the most cost-effective solution in the long term.
Tips for Caring for a Gas Heating System
How can a homeowner reduce their chances of dealing with a gas leak or faulty pilot light? Annual heating system maintenance is an important investment. Many property owners schedule the service in the fall to ensure the system makes it through winter without issue.
Schedule Fast and Reliable Gas Furnace Repairs
A1 Mechanical adeptly diagnoses the cause of a yellow flame in a furnace and promptly fixes any issues. We have over 40 years of experience in the industry and know the signs of a furnace about to explode and other important factors. Whether you need emergency repairs or routine maintenance, we’re passionate about keeping you safe and comfortable.
Call 502-708-2247 to schedule an appointment today.
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