We Now Provide Electrical Services!


We Now Provide Electrical Services!


We Now Provide Electrical Services!


Furnace Flashing Red Light: What Is Your Furnace Trying to Tell You?

The Short Answer Is: A blinking red light on a furnace typically indicates a system malfunction or an error code. Homeowners should refer to the furnace's user manual or the manufacturer's documentation to decipher the specific meaning of the flashing pattern. Depending on the code, it may suggest issues such as a faulty ignition system, a blocked air intake, or other operational problems. In most cases, if a homeowner is unable to resolve the issue based on the manual, it's advisable to contact a professional furnace repair company for diagnosis and repairs.

You've noticed something is not right with your furnace, so you walk to go inspect it yourself. That's when you see it, glowing like a panic button, a flashing red light on your furnace.

Don't panic though! Your furnace can't talk (unless you live in the Home Alone house) so this is how your system communicates to you and HVAC technicians that something is wrong and what specifically.

As a homeowner, it’s important to understand the significance of this warning signal and take the necessary steps to address the issue. In this guide, we will go over some of the common reasons why your furnace might be flashing a red light and what you can do about it.

What Does the Blinking Red Light on Furnace Panels Mean?

One important feature of furnaces is their blinking light system, which displays error codes for any issues that may be present in the system. In essence, a system problem will trigger a specific blinking pattern, which can be meaningful to a competent technician or even to a savvy homeowner.

"Furnace manufacturers typically design these codes to facilitate troubleshooting, making it easier for homeowners or technicians to diagnose and fix any present system problems," says Director of HVAC Service at Williams Comfort Air Roger Elkins. "It's like its own language with each light pattern indicating a specific issue."

If you're curious about what the furnace light means, check your owner's manual, which includes a code chart that explains what the blinking light codes mean. With this furnace light system, homeowners can easily identify and understand any issues before calling a professional for repair.

Or you can simply call for emergency heating repair service from a local HVAC company and they'll know exactly how to read the issue and resolve it.

What Could a Red Blinking Light Mean?

Furnace Overheating

The most common reason why a furnace will flash a red light error code is due to overheating. The high limit switch monitors system temperature, detecting heat and turning the HVAC system off if it becomes too hot. If the temperature inside the furnace gets too high, a high limit switch will activate, causing the furnace to shut down for safety and the furnace light to blink. The high limit switch could be triggered due to a clogged furnace filter, an issue with the blower motor, or a blocked air duct.

To fix this, first, turn off your furnace and let it cool down. Then, check your furnace filter and replace it if it’s dirty. You should also make sure that all of your air vents are open and free from any obstructions. If the blinking light does not quit and you have a furnace lockout, you need a technician to reset the high limit switch in your heating system.

Flame Sensor Issue

Another common cause of a blinking red light error code on your furnace is a problem with the flame sensor. The flame sensor is responsible for detecting the presence of a flame in your furnace. If it is dirty or malfunctioning, your furnace will not be able to start. To fix this issue, turn off your furnace and locate the flame sensor. Use a soft cloth to gently clean the sensor. If the problem persists, you may need to replace the sensor entirely.

Ignition Failure

If your furnace fails to fire multiple times, it will likely flash a red light error code. This could be due to a variety of reasons, including a faulty ignition switch, a broken igniter, flame failure, or a clogged gas valve. To troubleshoot this issue, first, check to see if your furnace is getting gas. You should be able to hear the gas flowing. If you don’t hear any gas, it’s likely that your gas valve is clogged and needs to be cleaned.

Control Board Malfunction

Another possible reason why your furnace light is blinking an error code could be due to a problem with the control board. The control board is responsible for regulating the temperature and fan speed in your furnace. If you have a circuit board failure, your furnace will not function properly. To fix this issue, loose wires may need to be tightened or it may be necessary to have HVAC professionals replace the control board.

Gas Pressure Problems

Gas pressure issues can often result in a blinking furnace light, indicating that there is a problem with the system. Gas pressure must be maintained at a specific level within the furnace to ensure proper operation and safety. If there is an issue with gas pressure, the furnace may not be able to ignite or may experience intermittent failures in operation. When there is too much pressure, it can cause damage to the furnace and create a safety hazard. Too low, on the other hand, can prevent the furnace from working altogether.

There are several reasons why gas pressure issues may occur, including problems with the gas supply, a blocked gas line, a damaged gas valve or pressure switch, and other technical malfunctions within the furnace system. These issues can often be addressed through routine maintenance and inspection, such as checking gas line connections and ensuring the furnace is properly vented.

Furnace Error Codes By Brand

Different patterns of flashing furnace lights can mean different things depending on the brand of your system. Not to worry! Here are links to some popular furnace brands and explainations for what their specific furnace error codes are:

Address the Little Red Light Before Additional Problems Arise

A blinking red light on your furnace is a sign that there is a problem with your heating system. It’s important to quickly identify the cause of the issue and take the necessary steps to address it. When you see a furnace light, it's important to get a system check and contact a professional HVAC technician to help diagnose and repair the problem.

At Williams Comfort Air, our team of Indianapolis furnace repair experts is dedicated to ensuring that your home stays comfortable and warm all winter long. Contact us today to schedule service and let us find and fix the cause of your furnace's red blinking light so you can avoid any more problems with your heating system.

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