What Makes A Furnace Overheat?

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If you’re experiencing issues with your furnace, it’s important not to ignore them. Even small, seemingly insignificant symptoms could be signs of a bigger problem, such as an overheating furnace. To avoid potential danger and a heating emergency, it’s best to reach out to an HVAC contractor right away and schedule a visit to address the issue.

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Signs of an Overheating Furnace

If you’re concerned about the safety of your furnace, it’s important to keep an eye out for signs of overheating. An overheating furnace can put your family at risk of carbon monoxide poisoning and leave you vulnerable to the cold during winter. To help prevent these dangers, look out for the following warning signs and contact an HVAC technician if you notice them in your home:

1. Strong Aroma of a Burning Furnace

image of a homeowner plugging nose due to furnace burning odor

If you notice a burning smell in your home, your first thought may be to check the stove to see if something is on fire. If the smell isn’t coming from the kitchen, it could be coming from another heat source, such as your furnace. If the smell is strongest near the furnace, it’s important to pay attention to how long it lasts. A brief, intense smell of burning dust after a period of inactivity is normal and nothing to worry about. However, if the smell persists for more than 30 minutes, it could be a sign that your furnace is overheating and causing damage to its components.

2. Unusual Humming Noise from the Furnace

If you’re familiar with the sounds your furnace makes, you know that a steady hum is normal. However, if you start to hear strange noises, such as clacks or bangs, it’s important to take notice and investigate further. These noises could be a sign that your furnace is struggling to keep up and that its components are starting to malfunction.

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3. Heating System Shuts Down Unexpectedly

Furnaces are equipped with safety sensors that can automatically shut down the system in the event of excessive heat. This helps prevent damage and gives the furnace time to cool down before restarting. However, if the problem persists, the furnace will keep shutting down and restarting until the underlying cause is addressed.

What Makes a Furnace Overheat?

The overheating of a furnace is not a random occurrence. It is the result of specific conditions being present. The issue typically develops slowly, making it difficult to notice at first. However, each cause of overheating has a solution. Some of the most common causes of furnace overheating are:

1. Restricted Airflow in the HVAC Unit

image of a dirty furnace filter and hvac air filter replacement

When a furnace is in operation, hot air is produced and then circulated throughout the house via the ducts. The air passes through a filter before traveling through the ducts. If there are any blockages or obstructions along the path of the air, the flow of air will be restricted. This can cause heat to build up in the furnace, potentially exceeding its maximum operating temperature.

2. Dirty Heating System Interior

As air flows through the furnace, it may carry contaminants that eventually settle on the internal components of the furnace. These contaminants can cause damage to the components over time, especially if they are not regularly cleaned. For instance, the blower motor generates heat as it spins the fan blades. If it becomes dirty, it may not be able to dissipate heat effectively, causing the furnace to overheat. Similarly, the furnace coils, which are responsible for transferring heat, may become coated in grime, making it difficult for them to function properly and potentially leading to overheating.

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3. Furnace Short Cycling

Short cycling is a term used to describe the rapid starting and stopping of an HVAC system. This can happen for a variety of reasons, but the end result is that the system is not able to complete a full cycle of operation. Short cycling can cause stress on the internal components of the system, such as the motors, potentially leading to premature failure.

4. Poor Heating System Maintenance

The mechanical components of a heating system are subject to wear and tear over time. If one of these parts fails, it can cause the system to overheat. For example, a short circuit in a stressed fan blower can reduce the circulation of air and cause the internal temperature of the furnace to rise. The effects of wear and tear can be reduced by regular HVAC maintenance.

5. End of Furnace Service Life

If your furnace is overheating, it may be a sign that it is reaching the end of its useful life. If your furnace is old, it may have multiple failing components and other underlying issues that are difficult and costly to repair. In this case, it may be more cost-effective to replace the entire furnace rather than trying to repair individual components.


How is an Overheating Furnace Fixed?

If your furnace is overheating, it is important to leave the repair work to a trained HVAC technician. Attempting to fix the furnace yourself, especially if you are not experienced in HVAC repair, can be dangerous. To avoid risking injury, turn off the power to the furnace and call for emergency repairs.

What is the Service Life of a Furnace?

The average lifespan of a furnace is about 15 years. However, the actual lifespan of your furnace may be shorter or longer depending on how well you maintain it. Regular maintenance can help extend the life of your furnace by identifying and addressing potential issues before they become more serious.

If you’re unsure whether to repair or replace your old furnace, one way to make a decision is to compare the costs. If the cost of repairing the furnace is relatively low, it may be worth it to go ahead with the repair. However, if the cost of repairing the furnace is high, especially if it is more than half the cost of a new furnace, it may be more cost-effective to replace the entire system. Be sure to find a unit that has an impressive AFUE efficiency rating, such as a variable-speed furnace.

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Benefits of Annual Furnace Maintenance

image of the word important depicting furnace hvac maintenanceAs a homeowner, there are a few things you can do to maintain your furnace and keep it running efficiently. For example, you can replace the air filter on a regular basis and remove any clutter that may be blocking the flow of air through the furnace. These simple tasks can help ensure that your furnace is operating at its best.

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If your furnace is overheating, it is important to address the problem as soon as possible. Allowing the furnace to operate in this condition for an extended period of time can cause serious damage to the system and may even result in the release of dangerous carbon monoxide gas. If you notice that your furnace is shutting down, emitting a burning smell, or making loud noises, it is important to call a professional HVAC contractor right away.

Contact Townsend Energy For All Of Your HVAC Requirements

te logoTownsend Energy is a top provider of heating and cooling services in the area. Our team consists of highly trained, certified technicians who are experts in HVAC maintenance, repair, installation, and replacement. When you work with us, you can be confident that your HVAC system will be serviced by knowledgeable, experienced licensed professionals who are committed to providing you with excellent service.

At Townsend Energy, we offer competitive prices for heating and cooling services in the area. If you need an HVAC repair or replacement system, our team can help you choose the best option for your home and budget. To get a free, in-home estimate, give Townsend Energy a call today. Our team is ready to help you keep your HVAC system running at its best.

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