The pilot light is a system located near the bottom of a gas furnace, usually close to the burners. There is typically a small access panel and perhaps a viewing panel that allows you to see the pilot light. It should appear as a small blue flame, and a couple of thin metal pieces may be nearby. These are the pilot tube and the thermocouple.
Be aware that not all furnaces have pilot lights. Electric systems will not have one, and many gas models also use an electronic ignition that has no continuously burning flame.
We will look at how to locate and identify the pilot light. Also, you should know the safety protocols and what to do next if you have trouble dealing with the pilot. Likewise, you will learn how to troubleshoot the pilot light and when to call a technician.
Quick Takeaways
- The pilot light sits near the bottom of the furnace, usually behind an access panel.
- It is a small, blue flame that should be steady.
- Many pre-2010 gas systems have pilot lights.
- Later models may have electronic ignitions.
- Turn off the shutoff valve if you smell gas at all.
- Call a technician if the flame is yellow instead of blue.
- Likewise, call a technician if the pilot light keeps going out.
What Is a Furnace Pilot Light?
The gas in a furnace’s burners needs something to ignite it. Your furnace’s pilot light stays on, providing a small flame at the ready for whenever the heating cycle starts. This is sometimes referred to as a standing pilot light.
The most likely alternative is an electronic ignition. This is a system that uses an electric spark to light the burners. It doesn’t stay on. It only triggers when the heating cycle begins.
Where Is the Pilot Light on a Furnace?
Typical Pilot Light Location in Older Furnaces
Nearly all pilot lights sit near the bottom of the furnace, close to the burner assembly. A small access panel allows you to get into the pilot light to check it and also to reignite it if it goes out.
If you’re unsure about how to relight the pilot, many furnaces have printed instructions near or on the access panel door. Check the back side if you don’t see instructions anywhere else.
What the Pilot Light Looks Like
The pilot light should have a small blue flame that stands between a half-inch and an inch. There will be a small metal tube at the bottom that steadily streams gas into the pilot.
There will also be a metal rod nearby, called the thermocouple. This is a safety feature that verifies that the pilot is still on.
The system will cut out if the pilot light is off or turns too cold. Cutting the system off protects your home from potential gas buildup if a flame isn’t present to light the burners.
Why You Might Not See a Pilot Light at All
One strong possibility is that your house has a furnace with an electronic igniter. Many furnaces manufactured after 2010 have igniters.
An igniter should have a ceramic ignition element and a spark electrode. Some types look like sparkplugs from cars. However, hot surface igniters will look like a thin wire and glow bright orange when activated.
How to Tell If Your Furnace Has a Pilot Light
Most post-2010 systems have igniters, and most pre-2010 models have pilot lights. You can also check for a control knob, which indicates the presence of a pilot light. The manufacturer’s labels on the furnace should also tell you.
The big thing to remember is: do not guess. If you don’t feel 100% certain about finding the pilot light, contact one of our technicians.
Is It Safe to Check the Pilot Light Yourself?
In most cases, it is safe for you to check. Usually, you can look through the window. However, it is safe to remove the panel for a direct inspection on an older model.
The big exception is if you smell gas. This is a case where you should find the shutoff valve and then call for help.
Common Problems Related to Furnace Pilot Lights
The most common cause of pilot light problems is the buildup of carbon, dust, or dirt that obstructs the flow. Systems with drafts or poor ventilation may also blow out the flame.
Likewise, a failing thermocouple might falsely trigger a safety cutoff. Low gas pressure can have a similar effect.
In many cases, professional repair is a necessity. Other than an initial attempt at relighting the pilot, you should refrain from DIY solutions. Attempting to fix the furnace yourself could damage it and potentially lead to a gas leak.
Pilot Light vs Electronic Ignition Systems
| Feature | Standing Pilot Light | Electronic Ignition |
|---|---|---|
| Common in | Pre-2010 furnaces | Post-2010 furnaces |
| Operation | Burns continuously 24/7 | Ignites only when heat needed |
| Energy efficiency | Lower (wastes gas) | Higher (no constant gas use) |
| Maintenance needs | More frequent attention | Less frequent service |
| Reliability concerns | Can blow out from drafts | Electronic components can fail |
| Safety features | Thermocouple protection | Flame sensors, hard lockouts |
| Initial cost | Lower | Higher |
| Operating cost | Higher (constant gas use) | Lower (on-demand ignition) |
Professional diagnosis is important. We know how to safely work with gas. Likewise, we can safely clean pilot lights and burners if there is buildup.
When to Call a Furnace Repair Professional
Call one of our technicians immediately if you notice:
- The pilot light goes out repeatedly after being relit
- Any smells of gas
- A visible pilot but no heating cycle begins
- Evidence of buildup on the burners
Frequently Asked Questions
Where exactly is the pilot light on a gas furnace?
The pilot light is near the bottom of the furnace behind an access panel. You should see a steady blue flame if it’s working.
Do all furnaces have pilot lights?
No, more modern gas models usually have an electronic igniter. This is particularly common in models built after 2010.
Can I relight my furnace pilot light myself?
Yes, if the instructions for doing so are clearly present somewhere on the furnace. Turn the gas valve off and wait five minutes, and then follow the instructions. If you’re not 100% comfortable with any of this, contact us.
Why does my pilot light keep going out?
Low gas pressure, a dirty pilot tube, a faulty thermocouple, or a draft may cause a pilot to keep going out. There is some risk of gas leaking, so pay attention to potential smells. Failures require professional assistance, which is just a phone call away.
Is a pilot light dangerous?
A pilot light is safe when working properly. However, a pilot light failure increases the risk of a gas leak or accumulation that could cause an explosion. Likewise, carbon monoxide can build up if the flame is weak, usually meaning it is yellow or orange.
Pilot Light Out? Call Us
One Hour Air Conditioning & Heating is ready to visit homes in Clearwater, FL, and the surrounding area. We are here to help if your pilot light has problems, your furnace won’t start, or there isn’t any heat. Our technicians are committed to punctuality. We’re always on time, or you don’t pay a dime.
Repairing a faulty pilot light or furnace is important. If you’re worried about the furnace in your Clearwater home, contact One Hour Air Conditioning & Heating immediately.