As the temperatures drop, the last thing you want is for your furnace to stop working. Sadly, furnaces don’t last forever, and there are many things that can go wrong with them at the worst possible time. From clogged filters to malfunctioning thermostats, it’s easy for minor problems to snowball into more significant, more expensive repairs. Understanding the common reasons why your furnace could stop working—and how to prevent them—can save you both money and stress. Here are the reasons why your furnace might fail and how you can keep it running.
1. Clogged or Dirty Filters
One of the most common reasons your furnace could stop working is a dirty or clogged filter. The air filter in your furnace is designed to trap dust, dirt, and debris, ensuring that only clean air circulates through your home. However, over time, the filter can become clogged with all the particles it catches. When this happens, the airflow through the furnace is restricted, causing the system to overheat, run less efficiently, and possibly shut down.
A furnace that’s struggling to breathe because of a dirty filter is more likely to overheat. This could cause your furnace to trip the high-temperature limit switch, which automatically turns the system off to prevent damage. Not only does this lead to an unexpected stop in service, but it can also force your furnace to work harder, driving up your energy bills.
The solution is simple: change your filter regularly. Depending on the type of filter your furnace has, you should change it every one to three months or more often if it’s heavily used. If you have pets, allergies, or live in a dusty area, you should replace it more often.
2. Ignition or Pilot Light Trouble
Another reason your furnace might stop working is the ignition system or pilot light. If you have an older furnace with a pilot light, it’s crucial to ensure that the flame is steady and strong. A weak or flickering flame can cause the furnace to malfunction, as it won’t be able to adequately heat the air in the system. If the pilot light goes out, the furnace simply won’t start.
For newer furnaces, the ignition system works electronically. The igniter lights the burners that create heat. If the igniter malfunctions or gets dirty, it may not ignite the gas properly, which means your furnace won’t produce heat. The system might also detect this issue and shut itself down as a safety measure to avoid gas buildup.
Check the pilot light (for older systems) or the igniter (for newer systems) first if your heater won’t light. If the pilot light goes out, you can relight it by following the directions on the package. For newer furnaces, the problem might be an igniter that needs to be replaced. It’s always best to call a professional for furnace repair, as dealing with gas systems can be dangerous. Regular maintenance of these components can keep ignition issues at bay and prevent a cold home.
3. Thermostat Issues: Your Furnace Isn’t Getting the Right Signals
Your thermostat is the brain of your furnace — it tells the system when to turn on and off to maintain a comfortable temperature. If the thermostat isn’t working correctly, your furnace might not get the signal to start heating. This can happen if the thermostat is old, broken, or miscalibrated. In some cases, your furnace might turn on and off erratically, leading to uneven heating throughout your home.
A faulty thermostat can cause your furnace to run inefficiently, wasting energy and driving up heating costs. In some cases, you might notice that your furnace is running nonstop even when the temperature is already comfortable. Or it might run for 5 to 10 minutes instead of the regular 15-minute cycle.
The first step in troubleshooting thermostat problems is to check the settings and batteries (if applicable). If everything looks correct, but the issue persists, it may be time for a replacement. Many newer thermostats are programmable, allowing you to set precise heating schedules that can improve energy efficiency. If you have an old, manual thermostat, consider an upgrade to ensure consistent performance and reliable temperature control.
4. Dirty Burner or Heat Exchanger
The burner and heat exchanger are two key components of your furnace. The burner lights the fuel, which generates heat, while the heat exchanger distributes that heat throughout your home. If either of these parts becomes dirty or clogged, the furnace will struggle to heat your home efficiently and may eventually fail altogether. Dust, dirt, and other particles can build up over time on the burner and heat exchanger, reducing their ability to perform correctly.
It’s possible for a dirty burner to overheat or fail to produce enough heat. A clogged heat exchanger can lead to carbon monoxide buildup, which is dangerous and could result in a system shutdown. This is a serious issue, as carbon monoxide is colorless, odorless, and potentially lethal.
If you suspect that your furnace’s burner or heat exchanger is dirty, it’s essential to schedule a professional inspection. These components are tricky to clean on your own, and attempting to do so without the proper knowledge or tools can lead to further damage. Regular professional maintenance can help prevent these issues and ensure that your furnace is always functioning at its best.
5. Pilot Control Valve and Your Gas Supply
If your furnace is powered by gas, another potential reason for a furnace failure could be an issue with the pilot control valve or gas supply. If there’s a gas line disruption or a valve malfunction, the furnace may not ignite. This is a serious concern because, without a steady supply of gas, your furnace won’t produce heat.
The gas valve itself could be faulty or blocked by debris. If it is not working properly, it may prevent gas from reaching the burners, causing the furnace to shut down. Additionally, the furnace may not receive enough gas pressure to ignite or stay lit.
6. Missing Routine Maintenance
One of the biggest reasons furnaces stop working is simply the need for more regular maintenance. Like any piece of machinery, your furnace needs periodic inspections and tune-ups to ensure it operates efficiently. Many furnace issues begin as minor problems that go unnoticed until they become more severe. Regular furnace maintenance helps detect these issues early before they turn into expensive repairs or complete system breakdowns.
Call Us for Your Furnace Needs
Preventing furnace failure starts with being proactive and paying attention to the signs that something might be wrong. If you’re unsure about the condition of your furnace or want a professional inspection, don’t hesitate to reach out to Air Care Heating & Cooling. We also offer boiler, furnace, AC, ductless mini-split, geothermal repairs, installation, and maintenance services, including air purifiers, whole-house humidifiers, water heaters, and commercial HVAC services.
Contact Air Care Heating & Cooling for heating and cooling service, and we’ll send one of our technicians to help you today with your Shawnee’s home HVAC system.
