Troubleshooting Your Furnace: What to Do When You Hear Unusual Noises

Troubleshooting Your Furnace: What to Do When You Hear Unusual Noises

It’s the middle of winter and the last thing you want to hear is a strange noise coming from your furnace. A furnace that’s working correctly should operate relatively quietly and any unusual sounds coming from it is a sign of a problem. If you find yourself in this situation, don’t HVAC panic. Troubleshooting your furnace can be a simple and straightforward process. There are several key steps to take to identify the source of the noise and determine what kind of repair is needed. By following this guide, you can learn how to troubleshoot your furnace and get it back to working order.

Common Furnace Noises and Potential Causes

If your furnace is making strange sounds, there are several potential causes you should be aware of. These can include: - A clogged filter: The air filter on your furnace should be inspected and cleaned on a regular basis. If it gets clogged or dirty, it can put extra stress on your furnace and cause it to work harder. If your furnace overheats, it can cause damage and lead to costly repairs. A clogged air filter can also lead to reduced air flow and cause the furnace motor to work harder. This can cause the motor to become louder and generate more vibration. - Dirty motor: The motor in your furnace needs a certain amount of lubrication to work correctly. If it becomes dirty, the motor can become noisy or even seize up and stop working. Luckily, this is an easy problem to diagnose and repair. - Issues with the blower fan: This is the part of the furnace that pushes warm air through the ductwork and out into your home. If the blower fan becomes damaged or jams, it can cause significant vibration and noise. This can lead to extensive damage to the furnace and the blower fan may need to be replaced. - Not enough voltage: Your furnace requires a certain amount of voltage to operate correctly. If the voltage is too low, the furnace won’t be able to operate correctly and can cause noise as a result.

What to Do If You Hear Unusual Noises

If your furnace starts making unusual noises, the first thing you should do is turn it off. If you do not have the ability to turn the furnace off at the thermostat, turn the circuit breaker off at the electrical panel. If you leave the furnace running while you are trying to troubleshoot the noise, you could cause even more damage. Once the furnace is off, it’s time to investigate. First, look to see if there’s any visible damage. You may see something blocking the air flow or a damaged fan blade that’s causing vibration. If you don’t see any obvious damage, look for the furnace’s error code. Many furnaces will light up an error code when there is a problem. If there’s an error code, it will give you a good indication of what the problem is. Now that you’ve identified the problem, it’s time to troubleshoot.

How to Diagnose the Problem

Once you’ve determined the kind of problem your furnace is having, the next step is to diagnose the cause. This can be broken down into three simple steps: - Identify the problem: As we’ve discussed, you need to know what the problem is before you can start troubleshooting. Start by looking for visible signs of damage or wear. If you see something that doesn’t look right, it could be the cause of the problem. - Consider the possible causes: Next, you need to determine what could be causing the problem. There are several different causes for furnace noises and issues. Once you’ve identified the problem, it’s time to consider the possible causes. - Perform some basic troubleshooting: Once you’ve identified the problem and the possible causes, it’s time for some basic troubleshooting. This will help you narrow down the potential causes and find the source of the issue.

How to Troubleshoot Your Furnace

Once you’ve diagnosed the problem, you can start troubleshooting to determine the cause. There are several common issues that can cause serious furnace noises, including: - Clogged air filter: This is one of the most common issues that can cause your furnace to make noise. An air filter that isn’t cleaned regularly can become clogged with dirt and dust. This can put additional stress on the furnace and make it work harder. It can also reduce the amount of air flowing through the furnace, leading to overheating. - Damaged blower fan: The blower fan is responsible for pushing warm air from the furnace through the ductwork and into your home. If the blower becomes damaged or jams, it can cause significant vibration and noise. - Low voltage: If the voltage supplied to your furnace is too low, it may not be able to operate correctly. The furnace may make noise as a result of this issue.

Furnace Maintenance Tips

There are several simple ways you can keep your furnace in good working order and avoid costly problems. These include: - Clean your filter regularly: As we’ve discussed, a dirty filter can cause your furnace to overheat. Make sure to clean your filter regularly to ensure it stays clean. - Repair any duct leaks: If you have a leak in your ductwork, it can cause your blower fan to work harder. This can lead to vibration and noise. - Inspect the furnace regularly: Give your furnace a regular inspection to make sure everything looks good. If you find any signs of damage, make repairs as soon as possible to avoid costly problems. - Contact a professional: If you are experiencing issues with your furnace, it’s best to call a professional. They will be able to identify and repair the issue quickly. - Communicate with your contractor: Let the contractor know exactly what is happening with the furnace. This will help them diagnose the problem quickly and repair it properly.


A furnace that’s making strange noises is a sign of a potential problem. It’s important to identify the cause of the noise and troubleshoot the issue quickly. If you keep your furnace maintained and clean, it should last for years without issue. If your furnace starts making unusual noises, follow this guide to diagnose the problem and repair it.

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