A malfunctioning furnace in the middle of winter can be frustrating and uncomfortable, especially when you rely on it to keep your home warm. If your furnace isn’t turning on, it’s important to act quickly to resolve the issue before it becomes more complicated or causes further damage to your system. Before you panic and call in a professional, there are several simple troubleshooting steps you can take to figure out the problem. Here’s a guide to help you identify the most common reasons why your furnace won’t turn on and what you can check first.
Check the Thermostat Settings
One of the most common reasons your furnace isn’t turning on is that the thermostat is set incorrectly. Before diving into more complex troubleshooting, ensure the thermostat is set to “heat” mode and the temperature is set higher than the current room temperature. If your thermostat is battery-operated, try replacing the batteries to ensure it’s functioning properly.
If your thermostat is a digital model, ensure that the display is working. Sometimes the display may freeze or malfunction, leading you to believe the furnace isn’t responding when, in fact, the thermostat is the problem.
Inspect the Circuit Breaker
Another common cause for a furnace that won’t turn on is a tripped circuit breaker. If there is an electrical issue, such as an overload or a short circuit, the breaker will trip to prevent damage to your furnace and other connected electrical systems. Check your electrical panel and ensure the breaker connected to your furnace is in the “on” position.
If the breaker has tripped, flip it off and on again to reset it. If the breaker trips again immediately or shortly after, it could be a sign of a deeper electrical issue, and you should contact a professional HVAC technician to investigate further.
Check the Furnace’s Power Switch
Many furnaces have a power switch located near the unit or on the side of the furnace. If this switch is turned off, your furnace won’t operate. Check to ensure that the power switch is turned on. It’s an easy step to overlook, but it’s a simple solution if your furnace isn’t powering up.
Inspect the Furnace’s Air Filter
A clogged or dirty air filter can cause your furnace to overheat, resulting in a safety mechanism that shuts it off to prevent damage. If you haven’t replaced your furnace’s air filter in a while, this could be the reason why it’s not turning on. A blocked filter restricts airflow, causing the system to work harder and potentially causing it to overheat.
Check your furnace filter and replace it if it’s dirty or clogged. A new, clean filter can improve your furnace’s performance and airflow, potentially resolving the issue of it not turning on.
Check the Gas Supply
If you have a gas furnace, ensure the gas supply is turned on. If the gas valve to your furnace is closed or restricted, your furnace will not receive the fuel it needs to operate. Check the gas valve near the furnace and ensure it is fully open.
You can also check to make sure other gas appliances in your home (like the stove or water heater) are working. If these aren’t functioning, there may be an issue with the gas supply, and you should contact your gas utility company to inspect the system.
Examine the Pilot Light or Ignition System
If you have an older furnace, it may have a pilot light that needs to be ignited manually. If the pilot light is out, your furnace won’t turn on. Follow the manufacturer’s instructions to relight the pilot light. Be sure to wait for a few minutes for any lingering gas to dissipate before trying to relight the pilot.
For newer furnaces with an electronic ignition system, a malfunction in the ignition system can prevent the furnace from turning on. If you suspect an issue with the ignition, it’s best to contact a licensed technician to inspect and repair the system, as this can be more complicated and may require specialized tools.
Look for Error Codes or Flashing Lights
Many modern furnaces are equipped with diagnostic lights that can help identify the problem. If your furnace has a status light, take note of any flashing patterns or error codes displayed. These codes can provide valuable insight into what is wrong with the furnace.
Check your furnace’s manual or the manufacturer’s website to decode any flashing patterns or error codes. If you’re unsure or the manual doesn’t provide enough information, call a professional HVAC technician for further assistance.
Check the Furnace’s Limit Switch
The limit switch is a safety feature designed to prevent the furnace from overheating. If your furnace is overheating, the limit switch will shut it down to prevent damage. If the limit switch has been tripped, it could indicate a deeper issue, such as a clogged filter, blocked vent, or malfunctioning blower motor.
If the limit switch has tripped and the furnace won’t turn back on after replacing the filter, it may require professional inspection to ensure that there are no underlying issues causing the furnace to overheat.
Look for Signs of Wear and Tear
Over time, components of your furnace can wear out, including the blower motor, capacitor, or other critical parts. If your furnace is over 10-15 years old, it may be showing signs of age. If none of the above steps have solved the problem, it could be an indication that a major component has failed and needs to be repaired or replaced.
In these cases, contacting a professional HVAC technician is essential to determine whether a repair or replacement is the best course of action.
Conclusion
A furnace that won’t turn on can be caused by several factors, from simple issues like a tripped breaker or dirty air filter to more complex problems like ignition system failures. By going through these basic troubleshooting steps, you can identify and possibly resolve the issue quickly.
If you’ve tried these steps and your furnace still won’t turn on, it’s time to call in a professional HVAC technician to assess the problem and make the necessary repairs. At Texas Air Authorities, we’re always ready to help with any furnace issues you may face. Our NATE-certified technicians are just a call away, and we offer same-day appointments to ensure your home stays warm and comfortable throughout the winter months. Contact us today to schedule an appointment or get a free quote for furnace repair!
Texas Air Authorities is the premier choice for HVAC services in Arlington. With a team of highly trained and certified technicians, we have the expertise to handle all of your heating, ventilation, and air conditioning needs. Our commitment to customer satisfaction is unmatched, and we always go above and beyond to ensure that your experience with us is positive. We use only the highest quality parts and equipment to ensure that your HVAC system is running at peak performance. Plus, we offer competitive pricing and flexible scheduling to fit your needs. Choose Texas Air Authorities for all of your HVAC needs in Arlington.
