Furnace Error Codes: What they Mean and How to Fix Them

When you operate a gas or oil furnace, you need to check for issues that may indicate a bigger problem or defects. These devices are complicated and have many moving parts. You should monitor the performance of your furnace and take note of any potential signs of trouble. Utilizing a gas or oil-powered furnace is not as simple as switching it on and off when needed. They are complex machines with many sensors and failsafe processes that have to be managed correctly to avoid issues in their operation. When we talk about operating these devices, what we’re referring to is the control system, which includes the thermostat that manages the heat level, an emergency switch that cuts off power in case of danger, and other safety features, as well as the various error codes they might trigger if something is amiss.

Identifying Gas Or Oil Furnace Error Codes

You can identify potential issues with your furnace by keeping an eye on the error codes it may trigger. These are displayed on the control panel of the furnace, so you’ll have to open the panel to see them. You can also use a furnace error code chart to determine the issue and then take steps to repair or fix it. Some of the most common error codes you may come across include: – Blower motor won’t start: This is the first stage of operation, where the blower motor kicks in when the thermostat is satisfied with the temperature setting. If this doesn’t happen, it means the motor is faulty and needs to be replaced. Without the blower motor, you won’t be able to circulate warm air throughout your home. – Burner won’t light: When you turn on the furnace, the igniter should light the burners. If it doesn’t, you might have a faulty igniter, a bad flame sensor, or a clogged burner orifice. You may also have an issue with the thermostat. – Furnace overheats: If the furnace is overheating, you may have a clogged or damaged blower motor, an obstruction in the airflow, or a faulty sensor.

Check The Thermostat

The thermostat is one of the most important parts of your furnace control system. If it malfunctions or breaks, the furnace won’t be able to regulate the temperature. The thermostat is used to measure and control the temperature in your home. It does this by switching the furnace on when the temperature drops below a certain level, and then off again when the temperature rises above a certain level. If the thermostat isn’t working correctly, it could cause your furnace to run longer than necessary, use more energy, and put you at risk of carbon monoxide poisoning. You should clean the thermostat to remove any dust or debris that may be interfering with its functionality. You can also replace the thermostat if needed.

Check The Air Filters

The air filters are primarily used to remove dust and allergens from the indoor air. When they’re clogged with dust, they can create resistance that interferes with the smooth flow of air. This can cause your furnace to use more energy than necessary and could lead to it shutting down, or it could trigger an error code. You should clean the air filters at least once a month to ensure the smooth operation of your furnace. You should also check to see if your furnace has a bag or a filter that requires changing. These types of filters are used to collect debris from the indoor air, so it’s important to change them regularly. When these filters are clogged with dust, they can cause your furnace to use more energy than necessary, which could lead to your utility bills being higher than usual. They could also cause your furnace to overheat, which could damage the furnace and shorten its lifespan.

Check The Burner Orifice

The burner orifice is the opening where the gas enters the furnace. This controls the flow of fuel into the combustion chamber. If the orifice is clogged, it could trigger an error code. You can clear the obstruction using a wire bristle brush. Make sure the opening is free of dust and debris. The burner orifice is used to regulate the amount of fuel entering the combustion chamber. If there is too much fuel entering the chamber, it could lead to an overheating furnace. If there is too little fuel entering the chamber, it could lead to a drop in pressure and reduced fuel flow.

Check The Combustion Chamber

The combustion chamber is used to mix oxygen with fuel to create a chemical reaction that generates heat. When there’s too much or too little fuel in the combustion chamber, it can trigger an error code. When there is too much fuel, it could lead to an overheating furnace, or when there is too little fuel, it could lead to a drop in pressure and reduced fuel flow. You may need to clean the combustion chamber if there is excessive dust or dirt. You can use a vacuum cleaner to suck up the dust. You should also check that there is enough air entering the combustion chamber. If there is not enough air, it could cause your furnace to remain turned off.

Repairs You Can Instantly Make

There are several repairs you can make to your furnace that require no special tools or expertise. You should check the ground wire to make sure it is clean and free from debris, as well as the ground screw where the wire connects to the furnace. You can also check the thermostat connection to make sure it is clean and free from dust and debris that may interfere with its functionality. You should also check the air filters and make sure they are clean, as well as the combustion chamber to remove any dust or dirt that may be trapped inside. When you keep your furnace and its components clean, it will run more efficiently and last longer. Another repair you can make is to replace an old thermostat with a new, modern one that has features like remote temperature control, home and away modes, and more. A new thermostat can make your furnace more efficient and save you money on your energy bill.


Furnaces are complicated machines that require proper operation and maintenance to avoid issues with their functionality. Some of the issues that can occur are due to faulty parts, clogs, and other problems that cause the furnace to function improperly. You can identify potential issues with your furnace by keeping an eye on the error codes it may trigger, as well as by checking the various components of the furnace control system for defects.