What causes a blinking red light on furnaces?
Grasshopper Heating & Cooling can determine whether you have a problem with your heat exchanger, gas pressure, or something else. We’re New York’s trusted source of diagnostics and repairs for all furnace models in the Albany, NY area.
Here, we discuss the most common reasons behind your furnace’s blinking red light.
Most Common Reasons You See a Blinking Red Light On Furnaces
If a red furnace light blinks or flashes, you can assume one thing right off the bat: the furnace isn’t functioning properly! An HVAC system professional will read the error code specific to your unit’s problem, but one of the following issues is likely:
A Flashing Furnace Light Can Mean You Have Igniter Failure
A professional HVAC technician can determine if your furnace light flashes because your unit has ignition issues. In a gas furnace, this component ignites your fuel so that your device can heat the air. Ignition problems can occur for several reasons, such as:
- A dirty flame sensor
- A dirty burner chamber or combustion chambers
- A faulty gas valve
- A vent blockage
- Reduced airflow from clogged furnace filters or a faulty blower motor
- Lack of a hot flame or pilot light (it looks like a yellow light)
- Flame failure from broken burners
A Blinking Light Can Indicate a Roll-Out Switch (High Limit Switch) Problem
Do you sometimes see a blinking red light on furnaces? Your roll-out switch provides an essential safety feature by shutting off your device when it overheats. If the high-limit switch doesn’t accurately read the internal temperature, it may shut down your device and activate the error code light.
This occurs most often when you have clogged air filters and dirt buildup.
You Could Experience a Heating System Lock Out
A lock-out is another safety feature in modern furnaces.
Your furnace has several sensors that monitor conditions within your furnace. If they sense an issue, they shut down your device. You’ll see a blinking red light.
Do You Have Thermostat Issues?
One issue homeowners often overlook in the furnace manual includes that a furnace’s blinking red light can occur when your thermostat malfunctions.
Can your thermostat not properly communicate with your heating system? It may activate your furnace’s blinking red light to show the right error code.
Related article: How high can I turn up my thermostat?
You May Have Heat Exchanger or Power Issues
You may see an error code if your furnace components aren’t receiving power correctly. Several issues can cause power problems, such as:
- Circuit board failure
- Issues with your circuit breaker box
- Loose wire connections
- Old wiring
- Frequent power surges
Do You Have Problems with Your Gas Valve?
A gas valve issue remains the most common cause of a blinking red light on furnaces. This occurs most often when the gas flowing into your furnace doesn’t have enough pressure to ignite.
Only a professional HVAC technician should handle issues with your gas supply.
Is Your Pressure Switch Malfunctioning?
Your furnace’s pressure switch shuts off power to your device when it detects unsafe pressure levels. If you have pressure switch problems, it could misread the pressure and turn off the furnace unnecessarily.
An HVAC professional can help determine if you have a malfunction or if you have increased pressure from the following complications:
- Blocked condensate drain
- Dirty air filters
- Improperly sized equipment
What Should You Do If Your Furnace Has a Blinking Red Light?
So, what should you do when you notice a blinking light on your furnace? You can perform basic diagnostics yourself to help determine the issue. Safely complete the following tasks:
- Check your recent utility bills. Do you have a decrease in your device’s energy efficiency?
- Inspect your device for clogged filters. Change them if necessary.
- Reset your thermostat. Try an extreme temperature. Does your furnace activate?
- Stay vigilant for unusual smells and sounds. The furnace may need repairs.
By performing initial troubleshooting, you can help your HVAC technician determine the source of your furnace problems.
Remember, if your furnace has problems during a period of extremely cold weather, you need it for safety. You should consider it an emergency and call for repairs immediately.
If you smell natural gas, exit your home immediately. Call for service from a safe distance.
Schedule Reliable Furnace Repairs Today
Now that you know how to handle a blinking red light on furnaces, contact Grasshopper Heating & Cooling. Our experienced technicians can interpret the error codes on all furnace brands, including your Carrier furnace. We can efficiently return your furnace to normal operation for a competitive price.
To schedule service, call 518-545-3271.
