Set the thermostat low, turn the gas control knob to OFF and wait five minutes. Turn it to PILOT, hold the knob or red reset button down, light the pilot and keep holding for about a minute. Release, then turn the knob to ON. This only applies to older standing pilot furnaces. If you smell gas, leave and call your gas supplier from outside.
To light a furnace pilot light, set the thermostat to its lowest setting, turn the gas control knob to OFF and wait five minutes, then turn it to PILOT and hold the knob (or the red reset button) down while you light the pilot. Keep holding for about a minute so the thermocouple heats up, release, and turn the knob to ON. This only applies to older furnaces with a standing pilot, and if you smell gas at any point, stop, leave the house and call your gas supplier from outside.
If you smell gas, do not light anything
Check for gas before you touch the furnace. Smell around the appliance and near the floor. Honeywell's homeowner instructions for its standing pilot gas valves point out that LP gas is heavier than air, so on a propane system the smell collects low.
If you smell gas, the same instructions say not to light any appliance, not to touch any electrical switch and not to use the phone. Leave the building and call your gas supplier, or the fire department if you cannot reach the supplier. PG&E's gas safety advice adds that cell phones, flashlights and matches can all be ignition sources, so make the call once you are a safe distance away. This is never a do-it-yourself step.
Does your furnace have a pilot light at all?
Many furnaces have no pilot light to relight. Carrier says standing pilots are found in furnaces made before the mid-1990s. Newer furnaces use electronic ignition, either a hot surface igniter or an intermittent pilot that lights only when the furnace calls for heat.
To find out which you have, turn the thermostat down, open the burner access panel and look. Carrier's test is simple: a small flame that burns all the time means a standing pilot. No steady flame and a circuit board inside the cabinet means electronic ignition.
The lighting label tells you too. Bryant notes that the relighting instructions are usually printed on the inside of the furnace door or cabinet. A standing pilot label tells you the pilot must be lit by hand. If your label says the furnace lights itself, do not try to light it with a flame.
If your furnace is the electronic kind and it will not heat, Carrier says the problem is more likely the igniter than a pilot. Our guide to a furnace blowing cold air covers those causes, and so does our furnace won't turn on checklist. If the control board is flashing a code, our Carrier furnace codes page explains how to read it. Oil furnaces have no gas pilot either; see why an oil furnace won't start instead.
How to light a furnace pilot light, step by step
These steps follow the homeowner lighting instructions Honeywell prints for its VR8200 standing pilot gas valve (form 68-0046-4), a common control on older furnaces. Honeywell itself says your furnace maker's instructions come first, because the controls and the order can differ. Read the label on your furnace before you start and follow it where it differs from this list.
You need a long-reach lighter or fireplace matches. Carrier says the pilot assembly is usually near the bottom of the cabinet, by the burner.
- Set the thermostat to its lowest setting.
- Turn off electric power to the furnace at its service switch.
- Remove the burner access panel, if your furnace has one.
- Turn the gas control knob clockwise to OFF.
- Wait five minutes so any gas in the combustion chamber can clear. Smell again, including near the floor. If you smell gas now, stop and follow the gas-smell steps above.
- Turn the knob counterclockwise to PILOT.
- Push down and hold the red reset button (on some valves you push the knob itself) and light the pilot.
- Keep holding for about one minute after the pilot lights, then release. The pilot should stay lit.
- If it goes out, turn the knob back to OFF and repeat from step 4.
- Once the pilot stays lit, turn the knob counterclockwise to ON, replace the access panel, turn the power back on and set the thermostat to the temperature you want.
The hold time varies by label. Honeywell says about one minute, Bryant says some furnaces need about 30 to 60 seconds, and Carrier's general steps say 20 to 30 seconds. When in doubt, hold for the longer time. Holding too briefly is the first thing Honeywell's service section checks when a pilot goes out on release.
Never force the knob or use a tool on it. Honeywell's instructions say that if the knob or reset button will not move by hand, or the reset button stays down after you let go, the gas control needs replacing by a qualified technician.
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What a healthy pilot flame looks like
Carrier describes a healthy pilot as a steady blue flame with a small yellow tip. Honeywell's installation notes say the flame should wrap around the top 3/8 to 1/2 inch of the thermocouple tip. A mostly yellow or orange flame points to incomplete combustion, and both Carrier and Bryant say that needs a professional, not another relight.
Why your pilot light won't stay lit
A pilot that lights and then dies when you let go of the button usually means the gas valve is not sensing the flame. The thermocouple is a small rod that sits in the pilot flame and makes a tiny current when hot. Honeywell explains that when the pilot goes out, or gets too small, the thermocouple's output drops and the gas valve shuts off all gas, pilot and burner.
Carrier and Bryant both name five causes. We add a sixth, letting go too soon, which is the first thing Honeywell's service steps check.
| Cause | What you see | DIY or technician |
|---|---|---|
| Button released too soon | Pilot lights fine, goes out the moment you let go | DIY: relight and hold for the full time on the label |
| Draft | Flame flickers or blows out, often with a door, vent or open panel nearby | DIY: close the door, put panels back, block the air source |
| Faulty or dirty thermocouple | Strong, steady flame, but it still dies on release after several careful tries | Technician |
| Dirty or clogged pilot orifice | Small, weak or flickering flame that does not reach the thermocouple | Technician |
| Gas supply problem | Weak, sputtering flame, or no gas at the pilot at all | Check the supply valve is open, then call the gas supplier or a technician |
| Failing gas valve | Knob or button stiff, reset button stays down, or no pilot gas with the supply on | Technician |
The thermocouple
Bryant calls the thermocouple the most frequent cause of a pilot that will not stay lit. Grime or wear stops it from making enough current to hold the valve open. Honeywell's service steps test it by measuring its voltage and replace it if the reading is out of range. As of October 2026, Carrier puts a technician's thermocouple replacement at about $150 to $250, with the part itself costing $5 to $30.
A dirty pilot orifice
The orifice is the tiny hole that feeds gas to the pilot. Dust can partly block it, which gives you a small flame that does not wrap the thermocouple properly. Cleaning it means taking apart the pilot assembly and its gas tubing, so we leave it to a technician.
Gas supply
Low gas pressure from the supply line can make the pilot sputter and go out, Carrier says. Honeywell's first check is that the main gas supply valve to the furnace is open. If other gas appliances in the house are also out, the problem is upstream of the furnace, so call your gas supplier. On propane, check the tank.
The gas valve
Bryant lists the gas valve among the parts that need a professional diagnosis. Honeywell's VR8200 manual says the valve has no parts you can replace and must not be taken apart. It must also be replaced if it has been flooded with water or shows physical damage.
What you can do and when to call a technician
Bryant calls relighting a standing pilot generally safe for homeowners if done carefully. Past that point, the work involves gas fittings and safety controls.
Safe for you to do:
- Relight the pilot following the label on your furnace
- Hold the button for the full time and try again
- Close off drafts and put every panel back
- Check that the gas supply valve to the furnace is open
Call a technician, or use our Find a Pro form, when:
- The pilot will not stay lit after two or three careful tries (Honeywell says to turn the knob to OFF and leave it there)
- The flame is mostly yellow, orange or weak
- The knob is stiff or the reset button sticks down
- The furnace has been in water
- You are not sure what kind of ignition your furnace has
After the pilot is back on
Turn the thermostat above room temperature and check that the main burners light. If they do not, go back to our cold-air guide for the other causes.
If your furnace has a standing pilot, it was most likely built before the mid-1990s. Our guide to how long a furnace lasts puts a typical gas furnace at 15 to 20 years, so a pilot that keeps failing is a good time to ask whether repair still makes sense. It is also a good moment to check how often to change the filter.
With any gas furnace, the CPSC recommends CO alarms on every level of the home and outside sleeping areas.
Frequently asked questions
How do I know if my furnace has a pilot light?
Turn the thermostat down, open the burner access panel and look. A small flame that burns all the time is a standing pilot. No steady flame and a circuit board inside means electronic ignition, which you should never try to light by hand. Carrier says standing pilots are found in furnaces made before the mid-1990s. The lighting label inside the furnace door also tells you which kind you have.
How long should I hold the pilot button down?
Hold it for the time printed on your furnace's lighting label. Honeywell's instructions for its VR8200 gas valve say about one minute after the pilot lights, Bryant says some furnaces need 30 to 60 seconds, and Carrier's general steps say 20 to 30 seconds. The hold gives the thermocouple time to heat up. If the pilot dies on release, holding longer is the first thing to try.
Why does my furnace pilot light keep going out?
The most common cause, according to Bryant, is a dirty or worn thermocouple that no longer holds the gas valve open. Other causes are a clogged pilot orifice, drafts near the furnace, low gas supply and a failing gas valve. You can fix drafts yourself. If the pilot still goes out after two or three careful relights, turn the knob to OFF and call a technician.
Is it safe to relight a furnace pilot light yourself?
Yes, if your furnace has a standing pilot and you follow its lighting label exactly. Bryant calls it generally safe for homeowners when done carefully. The rules that keep it safe: turn the knob to OFF and wait five minutes first, never force the knob or use tools on it, and never light anything if you smell gas. Electronic ignition furnaces are not lit by hand.
What should I do if I smell gas near my furnace?
Do not relight the pilot, touch light switches or use your phone near the furnace. Leave the house and call your gas supplier from a safe distance outside, or the fire department if you cannot reach the supplier. Honeywell's lighting instructions say to shut the manual gas valve to the appliance if you can, or the tank valve on propane.
Founder of Home Caprice. Benas started the site to simplify HVAC after dealing with the heating and cooling in his first apartment.
