If you've ever turned on your furnace on a chilly Georgia morning only to find it won't ignite, you're not alone. Many homeowners in Norcross, Buford, and throughout the Atlanta metro area experience furnace ignition problems during the winter months. Understanding the possible causes can help you troubleshoot the issue—or know when to call a professional.
Common Reasons Your Furnace Won't Ignite
Several factors can prevent your furnace from starting correctly. Here are some of the most common causes:
1. Thermostat Issues
Your thermostat serves as the brain of your HVAC system. If it isn't functioning correctly, your furnace may not receive the signal to turn on. Common thermostat issues include:
Incorrect settings (ensure it's set to "heat" and the temperature is higher than the current room temperature).
Dead or weak thermostat batteries.
Loose wiring or faulty connections.
2. Gas Supply Problems
Your furnace requires a steady supply of natural gas or propane to ignite. If your furnace isn't receiving enough fuel, it won't start. Possible gas supply issues include:
Closed gas valve - The valve may have been accidentally turned off. Check to make sure it's open.
Low gas pressure - This could be a larger issue with your gas service provider.
Blocked or leaking gas lines - If you suspect a gas leak, leave your home immediately and call your gas company or emergency services.
3. Faulty Ignitor or Pilot Light Issues
Modern furnaces use electronic ignitors instead of traditional pilot lights. If the ignitor fails, the furnace won't start. Signs of a bad ignitor include:
Clicking sounds when the furnace tries to start but doesn't ignite.
No visible spark or glow from the ignitor.
Burned-out or cracked ignitor.
For older furnaces with a standing pilot light, the flame may have gone out due to a draft or dirty thermocouple. You can try relighting it following your furnace's instructions, but professional repair is needed if it keeps going out.
4. Malfunctioning Flame Sensor
The flame sensor is a safety device that ensures the gas valve only stays open if a flame is present. If the sensor is dirty or broken, it may incorrectly shut off the gas supply before ignition occurs.
Signs of a dirty or malfunctioning flame sensor:
The furnace lights briefly but then shuts off.
No ignition at all despite the system running.
A professional HVAC technician can clean or replace the flame sensor to restore proper function.
5. Clogged Air Filter
A dirty air filter can restrict airflow, causing the furnace to overheat and shut down as a safety measure. Restricted airflow can also prevent proper combustion, making ignition difficult.
Solution:
Check your filter and replace it if it's dirty. Furnace filters should typically be replaced every 1-3 months, depending on usage and indoor air quality.
6. Tripped Circuit Breaker or Electrical Problems
Even gas furnaces rely on electricity to function. If a power surge or overload has tripped the furnace's breaker, it won't turn on.
How to check:
Go to your electrical panel and look for a tripped breaker.
If the furnace breaker is off, switch it back on.
If the breaker trips repeatedly, contact an HVAC professional.
7. Dirty Burners
Over time, burners accumulate dust, dirt, and debris, which can interfere with proper ignition. If your furnace clicks but doesn't light, dirty burners might be the issue.
Solution:
Cleaning furnace burners requires careful handling. If you suspect this issue, it's best to have a professional perform the cleaning.
8. Safety Switches & Limit Controls
Modern furnaces have built-in safety switches that shut down the system if overheating or other dangers are detected. If your furnace has a faulty high-limit switch, it may mistakenly shut off ignition.
Signs your safety switch is triggered:
Furnace repeatedly turns off after running for a few minutes.
No heat despite the furnace running.
If your furnace is shutting down frequently, professional troubleshooting is needed.
What to Check Before Calling a Professional
Before reaching out to an expert, try these simple troubleshooting steps:
- Thermostat Settings: Ensure it's on "heat" and set to the correct temperature.
- Gas Valve: Make sure the gas valve is open.
- Air Filter: Replace a clogged filter.
- Circuit Breaker: Check your home's electrical panel.
- Pilot Light: If your furnace has one, confirm it's lit.
If you've checked these and your furnace still won't ignite, it's time to call an HVAC professional.
When to Call a Professional
- While some furnace issues can be resolved with basic troubleshooting, other problems require professional expertise. You should call an HVAC technician if:
- You hear unusual noises (banging, whistling, or clicking sounds).
- You smell gas or suspect a gas leak (leave your home immediately and call for emergency help).
- Your furnace keeps shutting off after a few seconds. The ignitor, flame sensor, or gas valve needs replacement.
- You've tried troubleshooting and your furnace still won't ignite.
Professional Furnace Repair in Norcross, Lawrenceville & Atlanta Metro
At Bardi Home Services, we specialize in furnace repair, maintenance, and installation throughout Norcross, Lawrenceville, and the Atlanta metro area. Whether your furnace won't ignite or you need a seasonal tune-up, our experienced technicians are ready to help.
- Same-day and emergency services available
- Licensed, certified, and experienced technicians
- Upfront pricing with no hidden fees
- Serving Atlanta homeowners since 1989
Don't let a malfunctioning furnace leave you in the cold! Call Bardi Home Services today at (770)-288-5529 or schedule your service online.
