Dirty air filters are a frequent cause of furnace inefficiency. These filters trap dust, dirt, and debris, which can build up and restrict airflow. This blockage can cause the heat exchanger to overheat and the furnace to stop functioning properly.
A clogged air filter restricts airflow through the furnace. This leads to overheating and can cause the system to shut off because the safety switch shuts the unit down when high temperatures are reached. Check the filter and replace it if it's covered in debris.
There are several reasons why your furnace may not turn on. The most common include a broken thermostat, gas line issues, clogged air filters, blocked ductwork, a tripped circuit breaker, and issues with the furnace itself.
One of the most common furnace problems is a malfunctioning thermostat. A sure sign your thermostat isn't working properly is if your fan is constantly running. This will cause your thermostat battery to run, and cause your furnace to work inefficiently.
If the flame sensor fails, your furnace may not be able to start or may shut down shortly after starting. Common causes of flame sensor failure include corrosion, dirt buildup, or a broken wire. The gas valve controls the flow of gas to the furnace. If the gas valve fails, your furnace won't be able to produce heat.
The Average Furnace Lifespan
A well-maintained furnace can last at least 15 to 20 years, but completing annual maintenance and being diligent with repairs can extend its life even longer.
Check the pilot ignition light.
(Electronic ignitions will not have a pilot light.) If your furnace clicks on or initiates the start cycle, but does not fire up, you likely have a faulty or dirty ignitor/sensor. This is one of the most common furnace problems.
Reset any tripped breakers and adjust the thermostat to see if the furnace will come back on. If these don't work, you're at the stage where you need to call on a professional technician to look deeper into the failed furnace. Further tinkering risks damaged to the furnace—or to you!
Listen closely to your heating system. Unusual noises like banging, clanking or squealing might mean that there are issues with the furnace itself. If the system is constantly cycling on and off it could suggest thermostat malfunctions disrupting the regular heating cycle.
A clogged air filter is one of the most common reasons for a furnace shutting off unexpectedly. While it might sound like a minor issue, clogged air filters can significantly impact your system's performance.
If your furnace's problems continue, contact an HVAC expert. Also, if you notice discoloration when you check the pilot light, get professional help. If there are cold spots in your home, even though hot air is coming out of the air vents, the issue could be different from your furnace not working.
A furnace may short cycle when the heat exchanger is overheated, likely due to a lack of airflow. The heat exchanger is where the air gets heated. It will trip the furnace's safety switch when it gets too hot, which shuts down the operation to protect the system from dying.
Electric furnace installation tends to be the least expensive, ranging between $3,000 and $7,000, according to HomeAdvisor. Installing a natural gas furnace falls in the range of $3,800 to $10,000, and an oil furnace ranges $6,750 to $10,0000.
Your base homeowners policy will cover many types of damage to your furnace. An extra endorsement known as Equipment Breakdown Coverage (EBC) will give you additional coverage for certain types of mechanical or electrical failure.
Carrier furnaces typically have a small reset button inside the burner compartment. It may be red or yellow and is usually labeled “Reset.” If you're unsure where to find it, consult your furnace's user manual. Hold the button down for about 10 seconds before releasing it.
Mind the safety lock. When resetting your furnace, make sure to press the button only once to avoid engaging the safety lock. Reach out to professionals. In most cases, the safest course of action is to contact your go-to HVAC company if your furnace doesn't work after a power outage.
Leave the breaker(s) off for at least 10 minutes while the system is off and “rebooting.” After 10 minutes have elapsed, go back to the breaker box and flip the HVAC breaker(s) back on.
For people taking a proactive approach, doing a furnace replacement during the “shoulder seasons” of spring and autumn may offer lower prices, shorter lead times, and a better selection of products and service appointment availability.