How Do You Light the Pilot on a Furnace?
You may feel nervous when a furnace stops heating on a cold night. In most cases, the problem traces back to the pilot light. If the flame goes out, the furnace can’t warm your house. Learning how do you light the pilot on a furnace can help you know your system better and keep your home cozy and comfortable. Today, we’ll explain how the pilot works, why it goes out, safety measures to follow, and the steps to safely light a furnace. We will also explain when to call a professional if the flame refuses to stay lit. So let’s learn how to light the pilot on a furnace.
Understanding the Role of the Pilot Light
Before learning how do you light the pilot on a furnace, it is important to know what the pilot does. The pilot is a small blue flame located near the main burner. The flame sits just in front of the gas valve assembly. When the thermostat calls for heat, gas flows to the burner, and the pilot then ignites it.
If the pilot goes out, the burner won’t fire. Your home stays cold, and the furnace cycles without producing heat.
A gas furnace pilot light depends on a supply of natural gas. If anything disrupts that supply, the flame drops out. That’s the reason why the furnace won’t heat until the pilot is restored correctly.
Some signs the pilot is out include:
- Clicking sounds with no burner ignition
- No warm airflow
- A cold furnace cabinet
- No visible flame in the pilot chamber
Why the Furnace Pilot Light Goes Out
The pilot on your furnace can go out for many simple reasons. These include:
1. Gas Flow Problems
If the gas supply is interrupted, weak, blocked, or the pilot goes out. A faulty intake valve can also affect the movement of the gas.
2. Drafts or Air Movement
A sudden draft can blow out the furnace pilot. Remember that this is common in older units.
3. Dirt or Debris
Dust buildup can block pilot gas or clog the burner area.
4. Bad Thermocouple
A bad thermocouple is one of the most common issues. The thermocouple detects heat from the furnace pilot flame. If it senses no heat, it shuts the gas valve (for safety). When the thermocouple stops working, it sends false signals, and the flame will not stay lit.
5. Problems With the Ignition System
If the ignition device becomes worn or dirty, the pilot will not hold a flame.
Knowing about these issues helps you decide when you can relight the flame and when to call a professional.
Safety Steps Before Lighting a Pilot Flame
Before lighting the pilot on a furnace, follow basic safety precautions. The pilot sits near gas components, so safe handling is a must.
Check for a Gas Leak
If you smell gas, stop immediately. A gas leak can cause fire or carbon monoxide poisoning. So, do not strike a long lighter or match.
Leave the home immediately and call your gas provider if the smell continues.
Turn Everything to the OFF Position
Locate the gas valve knob on your furnace. Turn it to the “OFF” position as this stops the flow of gas. Wait a few minutes for any gas to disperse.
Read the Owner’s Manual
The owner’s manual gives instructions for your furnace model. Not every gas furnace is built the same, so check the labels and diagrams.
Check Ventilation
Open nearby doors or windows so fumes do not collect around the furnace.
Once these steps are done, you can move to relighting.
Note: We recommend not taking any risks when it comes to gas and fire. Always call a professional, as trained and experienced technicians handle these situations safely.
How to Relight the Pilot Light
Here is the general process for lighting the pilot on a furnace. Follow your furnace’s label or manual; steps may vary by model.
1. Locate the Control Knob
Find the control knob near the burner chamber. This knob has generally three settings:
- “OFF” position
- “Pilot” position
- “ON” position
You should see the openings near the flame area.
2. Turn to Pilot Position
Switch the gas valve knob to the “Pilot” position. This allows a small amount of gas to flow only to the pilot.
3. Hold Down the Button
Most furnaces require holding down a button to release pilot gas. PRESS and HOLD this button while lighting the flame.
4. Use a Long Lighter
Take a long lighter or a safety match and place the flame near the pilot opening. Once the gas catches, you’ll see a small blue flame.
5. Continue Holding the Button
Keep pressing the button for at least 20 to 30 seconds. This gives the thermocouple time to warm up. Once it detects heat, it will let the gas continue flowing.
6. Release Carefully
- After holding the button, slowly release it
- Watch the flame
- If the pilot light stays steady, you succeeded.
7. Turn the Knob to On
Once steady, turn the knob to the “ON” position so the furnace can begin heating.
If the flame drops again, a deeper issue may be causing it.
Learn more about why your furnace is blowing cold air and how to troubleshoot it.
When the Pilot Light Won’t Stay Lit
If the flame goes out again, even after holding the button, the problem might involve:
- Trouble with the flow of natural gas
- A damaged ignition system
- A bad thermocouple
- A gas line that is clogged
- Internal parts blocked by soot
At this point, relighting the flame repeatedly won’t fix the problem. This is when a trained HVAC technician should step in and fix the issue.
Pilot Light Color Matters
A healthy flame is a small blue flame. If the flame turns orange or yellow, the furnace may be burning gas incompletely. This can raise the risk of carbon monoxide inside your home, which is highly dangerous.
Discolored flames may indicate poor combustion of gas or dirty burners. Both require immediate inspection from the professionals.
How Furnace Pilot Designs Differ
Some older furnaces use a standing pilot light that burns constantly. Others ignite the pilot only when needed. Many newer furnace systems no longer use pilots at all. They use electronic ignition.
If you have a combined system that includes a water heater or air conditioner, you may notice similar terms, but the pilot procedure varies for each appliance.
Knowing the setup helps you recognize signs of trouble more easily.
Why You Should Call a Professional for Pilot Problems
Relighting the pilot is simple if the only issue was a temporary gas interruption. But when deeper problems exist, trying to relight repeatedly is risky. That’s why you should always call professionals, as they know:
- How to inspect the gas chamber
- Test the thermocouple
- Check gas pathways
- Confirm safe operation
- They also check for carbon monoxide poisoning risks and blocked ventilation.
If you notice constant clicking, repeated shutdowns, or weak flames, the safest solution is to get professional help.
Conclusion: Lighting a Pilot Light Safely Matters
Knowing how do you light the pilot on a furnace gives you a basic understanding of the heating system of your home. The steps involve switching to the correct settings, igniting the gas with a flame, and checking the pilot area for stable burning. If the pilot refuses to stay lit, the problem generally links to a gas flow problem, a bad thermocouple, or ignition problems.
A functioning pilot is important for safe operation. When things don’t look right, calling a trained technician protects your home and keeps your furnace working.
Call Greenstreet HVAC for Furnace Pilot Light or Heating Issue
If the pilot of your furnace keeps going out or your gas furnace won’t heat, Green Street HVAC can help. We offer Furnace Repair, Furnace Installation, Duct Cleaning, HVAC Maintenance, and AC Repair to keep your system running.
We are from Springfield, Tennessee, and we can inspect the pilot, test the gas flow, and restore proper performance to your heating equipment.
Call Green Street HVAC today to schedule service!
