Where Is the Pilot Light on a Furnace?

Where Is the Pilot Light on a Furnace?

If your furnace suddenly stops producing heat, one of the first things to check is the pilot light. The pilot light is a small flame that ignites the gas burners inside your furnace. If it goes out, your furnace won’t heat your home — no matter how high you turn up the thermostat.
In this guide, we’ll explain where to find the pilot light on your furnace, how it works, what to do if it goes out, and when to call a professional from HVAC Cupertino for help.

What Is a Pilot Light?The pilot light is a small, continuously burning flame that serves as the ignition source for your furnace’s burners. When your thermostat calls for heat, the furnace releases gas to the burners, and the pilot flame lights it instantly.
Modern furnaces may not use a traditional pilot light — instead, they have an electronic ignition system. But if your furnace is more than 10–15 years old, chances are it has a standing pilot flame.

Where Is the Pilot Light Located?In most gas furnaces, the pilot light assembly is located inside the burner compartment, near the bottom of the unit. Here’s how to find it:
1. Turn Off the FurnaceBefore doing anything, make sure your furnace is off. Set your thermostat to “OFF” and turn off the power switch on or near the furnace.
2. Locate the Access PanelThe pilot light is usually behind a small metal access panel on the front or bottom of the furnace. You may need to unscrew or slide it open to see inside.
3. Look for the Burner AssemblyOnce the panel is open, look near the burners — you should see a small gas tube leading to a pilot nozzle. The pilot flame burns just in front of this nozzle.
4. Identify the Control Knob and Reset ButtonNext to the pilot assembly, you’ll find a gas control knob labeled “ON,” “OFF,” and “PILOT.” There’s also a small red or black reset button used to relight the flame.
If you don’t see any of these components, your furnace likely uses an electronic ignition instead of a pilot light.

How to Check If Your Pilot Light Is OnLook through the small inspection window or access opening near the burner area.

• If you see a small blue flame, your pilot light is working.
  
• If it’s out or flickering, the flame needs to be relit or adjusted.
  
• If there’s no visible flame, your pilot light is completely out.
  

The flame should be steady and blue — a yellow or orange flame indicates poor combustion and possible dirt buildup on the nozzle.

How to Relight a Pilot Light If you’re comfortable doing so, you can relight the pilot yourself by following these steps:
Step 1: Turn the Furnace OffSwitch the gas control knob to OFF and wait at least 5 minutes to let any residual gas clear out.
Step 2: Turn the Knob to “PILOT”Once it’s safe, turn the knob to “PILOT.”
Step 3: Hold Down the Reset ButtonPress and hold the reset button while lighting the pilot with a long lighter or match. Continue holding the button for 30–60 seconds after the flame ignites.
Step 4: Turn the Knob to “ON”Once the pilot stays lit, release the reset button and turn the knob to “ON.” The main burners should ignite when the thermostat calls for heat.
⚠️ Important Safety Tip: If the pilot won’t stay lit after several attempts, or you smell gas, turn everything off immediately and call HVAC Cupertino for professional assistance.

Why Your Pilot Light Keeps Going OutA pilot light that keeps going out could indicate a larger issue with your furnace. Common causes include:

• Dirty pilot orifice: Dust or soot buildup can block gas flow.
  
• Faulty thermocouple: This safety sensor may fail to detect the flame properly.
  
• Drafts or ventilation issues: Airflow near the furnace can blow out the flame.
  
• Low gas pressure: Problems with the gas supply line can prevent the pilot from staying lit.
  

If you have to relight your pilot frequently, it’s time to schedule a professional inspection.

Pilot Light vs. Electronic IgnitionNewer furnaces no longer use standing pilot lights. Instead, they rely on:

• Hot surface igniters, which use heat to light gas burners.
  
• Spark igniters, which create a small spark when heat is needed.
  

These systems are more energy-efficient because they don’t burn gas continuously. If your older furnace still uses a pilot light, upgrading to a modern high-efficiency furnace could save you significant energy costs over time.

When to Call an HVAC ProfessionalWhile relighting a pilot light is a simple task, some problems require professional attention — especially if:

• The pilot light won’t stay lit.
  
• You smell gas near the furnace.
  
• The flame is yellow, orange, or flickering.
  
• You notice soot buildup or corrosion around the pilot assembly.
  

At HVAC Cupertino, our licensed technicians can:

• Inspect and clean your pilot assembly
  
• Replace faulty thermocouples
  
• Repair gas supply issues
  
• Upgrade old pilot ignition systems
  

Why Choose HVAC Cupertino?Serving Cupertino, CA, and nearby areas, HVAC Cupertino is your trusted local expert for heating, cooling, and furnace repair.
✅ Licensed & insured HVAC specialists
✅ Same-day furnace repair & safety inspections
✅ Honest pricing, no upselling
✅ Serving Cupertino, Sunnyvale, and Santa Clara
📞 Call us today at (408) 740-7079 or visit www.hvaccupertino.com to schedule a furnace service or safety check.
We’ll make sure your home stays safe, warm, and energy-efficient this winter.

COMMONLY Asked Questions ABOUT PILOT LIGHT ISSUES1. Where is the pilot light on my furnace located?It’s typically near the bottom of the furnace, inside the burner compartment behind a small access panel.
2. What does the pilot light look like?It’s a small, steady blue flame burning near the gas burners. A yellow or orange flame indicates a problem.
3. Can I relight my furnace pilot light myself?Yes, but always follow the manufacturer’s instructions carefully. If the flame won’t stay lit, call a professional.
4. What should I do if I smell gas?Turn off the furnace immediately, avoid using electrical devices, and call your gas company or HVAC Cupertino for emergency service.