Troubleshooting
Furnace Pilot Light Won't Stay Lit: Causes and Fixes
5 min read••
A pilot light that won't stay lit leaves you without heat. Understand why it happens and what you can do about it.
Older furnaces use a standing pilot light that burns continuously. If it won't stay lit, your furnace won't heat.
Safety First
Natural gas is dangerous. If you smell gas: - Don't light anything - Don't use electrical switches - Leave the house - Call the gas company
Common Causes
Thermocouple Issues The thermocouple is a safety device that detects whether the pilot is lit. If faulty, it shuts off gas even when the pilot is burning.
Dirty Pilot Orifice A clogged pilot opening produces a weak flame that won't heat the thermocouple properly.
Draft Problems Wind or air pressure changes can blow out the pilot. This might indicate venting issues.
Gas Supply Problems Low gas pressure or an intermittent supply can cause pilot problems.
What You Can Do
Clean the Pilot Turn off gas, wait for components to cool, then gently clean the pilot orifice with compressed air.
Check the Thermocouple Position The thermocouple should be in the pilot flame. If it's been knocked out of position, carefully adjust it.
Inspect for Drafts Look for sources of air movement near the furnace.
When to Call a Professional
If cleaning and positioning don't help, the thermocouple likely needs replacement. While this is a relatively simple repair, it involves gas system work that's best left to professionals.