Why Will My Furnace Not Turn On? Troubleshooting Tips You Need to Know
What To Know
- If the thermostat is wired incorrectly, it won’t be able to send the signal to the furnace to turn on.
- This could be due to a buildup of dust or dirt in the furnace, a blocked air filter, or a problem with the blower motor.
- If the limit switch keeps tripping, it’s a sign of a more serious problem that needs to be addressed by a professional.
The winter chill has set in, and you’re bundled up in layers, but your home feels like an icebox. You throw the thermostat switch, but the familiar hum of your furnace remains silent. “Why will my furnace not turn on?” you wonder, shivering in your own home.
This is a common problem, and it can be frustrating, especially when the temperature plummets. Thankfully, most furnace issues can be addressed with a little troubleshooting and potentially a professional call. This blog post will guide you through the most common reasons why your furnace might not be turning on, helping you identify the problem and take the appropriate steps to get your home warm again.
The Basics: Power and Pilot Light
Let’s start with the fundamentals. Your furnace needs power to operate, so the first thing to check is the circuit breaker.
- Check the Circuit Breaker: Locate the circuit breaker box in your home. Look for a tripped breaker, usually indicated by a switch that’s flipped to the “off” position. If you find a tripped breaker, reset it by flipping the switch back to the “on” position. If the breaker trips again immediately, it’s a sign of an electrical issue that needs professional attention.
- Pilot Light: Older furnaces often have a pilot light that needs to be ignited manually. If your furnace has a pilot light, make sure it’s lit. If it’s out, follow the instructions for relighting it in your furnace’s manual. If you’re unsure, call a professional.
Beyond the Basics: Common Furnace Problems
If the power and pilot light are working, then the problem lies deeper within the furnace’s mechanics. Here are some common culprits:
1. The Thermostat: The Brain of Your Heating System
The thermostat is the control center for your furnace. It tells the furnace when to turn on and off based on the temperature you’ve set.
- Check Thermostat Batteries: If your thermostat runs on batteries, replace them if they’re low.
- Thermostat Settings: Ensure the thermostat is set to “heat” and that the temperature is set higher than the current room temperature.
- Thermostat Wiring: If the thermostat is wired incorrectly, it won’t be able to send the signal to the furnace to turn on. This is a job for a professional.
2. The Blower Motor: Circulating Warm Air
The blower motor is responsible for pushing the warm air from the furnace through the ductwork and into your home.
- Blower Motor Fuse: Check the blower motor fuse. It’s usually located in the furnace’s electrical panel. If the fuse is blown, replace it with a fuse of the same amperage.
- Blower Motor Capacitor: The capacitor stores energy to help the blower motor start. A faulty capacitor can prevent the motor from turning on. If you suspect a capacitor problem, call a technician.
3. The Igniter: Lighting the Flame
The igniter is a small electrical component that sparks to ignite the gas or oil in your furnace.
- Igniter Failure: A faulty igniter can prevent the furnace from starting. If you see sparks but no flame, the igniter might need replacement.
- Igniter Wiring: If the igniter is wired incorrectly, it won’t be able to ignite the gas or oil. Again, a professional is needed for this issue.
4. The Limit Switch: Safety First
The limit switch is a safety device that prevents the furnace from overheating.
- Limit Switch Activation: If the limit switch is activated, the furnace will shut down. This could be due to a buildup of dust or dirt in the furnace, a blocked air filter, or a problem with the blower motor.
- Limit Switch Reset: To reset the limit switch, you’ll need to locate it in the furnace and press the reset button. If the limit switch keeps tripping, it’s a sign of a more serious problem that needs to be addressed by a professional.
5. The Air Filter: Clean Air, Efficient Operation
The air filter traps dust, dirt, and other debris from the air circulating through your furnace.
- Clogged Air Filter: A clogged air filter restricts airflow, which can cause the furnace to overheat and shut down.
- Air Filter Replacement: Replace the air filter every 1-3 months, or more often if you have pets or live in a dusty environment.
When to Call a Professional
While many furnace problems can be addressed with simple troubleshooting, some situations require professional intervention. Here are some signs you should call a heating and cooling technician:
- Electrical Issues: If you suspect an electrical problem, such as a tripped breaker that resets immediately or a faulty capacitor, it’s best to call a professional to avoid potential hazards.
- Gas Leaks: If you smell gas, evacuate your home immediately and call the gas company. Never attempt to troubleshoot a gas leak yourself.
- Recurring Problems: If your furnace keeps shutting down or experiencing the same problem, it’s time to call a professional for a thorough inspection and diagnosis.
- Unusual Noises: If your furnace is making unusual noises, such as banging, screeching, or rattling, it’s a sign that something is wrong and needs to be addressed.
Taking Care of Your Furnace: Prevention is Key
Just like any appliance, your furnace requires routine maintenance to run smoothly and efficiently. Here are some tips for keeping your furnace in top shape:
- Regular Inspections: Schedule an annual furnace inspection by a qualified technician to ensure everything is working properly and to identify any potential problems before they become major issues.
- Air Filter Replacement: As mentioned earlier, replace the air filter regularly to prevent dust and debris from clogging the furnace and affecting its performance.
- Keep the Area Clean: Keep the area around your furnace clean and free of clutter to prevent dust and debris from accumulating.
- Protect from the Elements: If your furnace is located in an unheated area, make sure it’s protected from the elements to prevent freezing pipes and other problems.
Time to Get Warm Again!
A malfunctioning furnace can be a major inconvenience, but with a little understanding of the common causes and some basic troubleshooting, you can often identify the problem and get your heating system back up and running. Remember, if you’re unsure about any aspect of furnace maintenance or repair, it’s always best to call a qualified professional for assistance.
Answers to Your Most Common Questions
Q: Why does my furnace keep turning on and off?
A: This is known as “short cycling.” It can be caused by a variety of factors, including a clogged air filter, a faulty thermostat, or a problem with the blower motor.
Q: How can I prevent my furnace from freezing?
A: If your furnace is located in an unheated area, make sure it’s protected from the elements. You can also insulate the pipes leading to and from the furnace to prevent them from freezing.
Q: What should I do if I smell gas?
A: If you smell gas, evacuate your home immediately and call the gas company. Never attempt to troubleshoot a gas leak yourself.
Q: How often should I change my furnace filter?
A: It’s recommended to change your furnace filter every 1-3 months, or more often if you have pets or live in a dusty environment.
Q: What is the best way to keep my furnace running efficiently?
A: Schedule annual furnace inspections, replace the air filter regularly, keep the area around the furnace clean, and protect it from the elements.