If your furnace is flashing green light, there’s no need to panic. In most cases, it simply means that the furnace is in standby mode and waiting for the thermostat to signal to turn on.
However, a flashing green light can also point to a particular issue – and we all know that furnace issues should be dealt with as soon as possible.
In this guide, we will present the most common furnace problems that the green light can point to and the best solutions.
Why is the green light flashing on your furnace?
If there is a blinking light on your furnace, it could mean that the appliance is in standby mode.
However, there are a few other possible scenarios you should look into, especially if you’ve noticed that your furnace hasn’t been functioning properly since the blinking green light was on.
Furnace has exceeded the number of times required for it to start
One of the possibilities is that the furnace is flashing green because it has surpassed the number of times necessary for it to start.
This means you should check the furnace’s air filter, as a dirty air filter prevents the furnace from starting.
What’s more, you should also check the furnace’s igniter. If the igniter is broken, then the furnace will not be able to start. A broken igniter must be replaced before the furnace can be used again.
It is also possible that the furnace is flashing green because of a gas line problem, including a line blockage or a leak.
If you suspect a gas line problem, you should call a professional to come and check it out. Do not try to fix it yourself, as this could be very dangerous.
Combustion process issue
Another possibility is that the furnace is flashing green because it has detected a problem with the combustion process.
Combustion in a furnace is a process that uses fuel and air to create heat. This heat is then used to warm the air in your home.
For combustion to occur, the furnace must have a way to bring in the fresh air, and it must also have a way to expel the exhaust from the combustion process.
If either of these things is not working correctly, it could cause the furnace to flash a green light.
This could be caused by an improper mixture of fuel and air or a blockage in the flue. If you see a green light flashing on your furnace, you must immediately call a furnace repair technician, as this could be a severe problem.
If the light on your furnace transitions from green to red, the unit is overheating, and you should turn it off immediately.
IFC circuit board issue
Another potential reason behind a flashing green light on your furnace is a faulty IFC circuit board.
If the IFC board is damaged, it can cause the furnace to overheat and shut down. If this happens, you’ll likely see a green light flashing on the control panel.
The role of the IFC board in your furnace is to control the flow of electricity to the furnace. In most cases, a flashing green light on the control panel indicates that the IFC board needs to be replaced.
How to fix the flashing green light in your furnace
Remember that most of these issues require professional service, and you should not attempt to fix them yourself.
However, we will discuss the best troubleshooting methods that could help you get to the bottom of the furnace flashing green light issue.
1. Check furnace elements
A blinking green light on your furnace could indicate that the appliance has exceeded the maximum number of attempts required for it to start due to a faulty or damaged furnace element.
To clean a dirty furnace air filter, remove it from the furnace and rinse it with warm water to remove dirt and debris. Allow the filter to dry out before returning it to the furnace.
If your furnace air filter is very dirty or damaged, you may need to replace it with a new one. Check your owner’s manual for the size and type of air filter you need for your particular furnace model.
To troubleshoot the furnace igniter, check for any cracks or damage in the furnace, and look for any loose wires that could be causing a problem.
If you find any damage, you’ll need to replace the igniter or have it replaced. It is also necessary to secure and tighten any loose wires.
Once you’ve done that, you should be able to restart the furnace and see if it ignites properly.
If the furnace still doesn’t ignite, there could be a problem with the gas line. In this case, it’s best to hire a professional and have them inspect the gas line and repair it if necessary.
2. Check the combustion process
If there is an issue with the combustion process in your furnace, you may notice flames that are either too low or too high.
These flames should be blue; if they are not, this could indicate a problem with the fuel-to-air mixture in your furnace.
If you see orange or yellow flames, this could mean that too much fuel is burned, which could even lead to a fire.
If the flames are very low, this could indicate a problem with the amount of oxygen supplied to the combustion chamber.
If you see any of these problems with the flames in your furnace, it is essential to have a professional inspect and service your furnace as soon as possible.
3. Check the IFC circuit board
To check if the IFC circuit board is causing your furnace to blink green, first ensure that the furnace is turned off, then disconnect the circuit board from the furnace.
Once it is disconnected, turn on the power to the furnace and see if it still blinks green. If it does, it may be time to replace the circuit board.
If your furnace is still blinking green after replacing the circuit board, there may be a problem with the blower motor.
To check the blower motor, ensure the power to the furnace is turned off. Then, remove the access panel and locate the blower motor.
Review the connections to ensure they are tight, and clean any debris around the blower motor.
Once you have done that, turn the power to the furnace and see if the blower motor starts running. You will need to replace the blower motor if it does not.
You shouldn’t attempt any of these methods if you don’t have any experience with similar tasks.
Hiring a professional to troubleshoot and fix your furnace is a much more reliable method, especially regarding your safety.
Adrian is an ISCET licensed professional that has completed the National Appliance Service Technician Certification Exam and has the expertise to diagnose and repair any appliance. He is well-versed in the latest technologies and techniques and is always up-to-date on the latest industry standards.
