Servicing Lancaster and Surrounding Areas

Why Won't My Furnace Light?

If the heat in your home doesn’t seem to be working, pay a visit to your gas furnace to see what the problem could be. If you notice the pilot light isn’t lit (and has a problem staying lit), this is a problem that will need to be fixed before you’ll be able to heat your home again. Here are a few reasons why your pilot light has been going out on you:

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Before You Start

Woah, not so fast! Before you begin working on your furnace, make sure the pilot light has been extinguished. You should then manually turn off the gas via the shutoff valve and wait at least a half hour for the furnace to cool down. Once this timeframe has passed, it will be safe to open up your furnace so you can take a look inside.

A Faulty Thermocouple

One of the most important parts of a gas furnace is the thermocouple. This piece has the job of checking to see if the pilot light is on or not by measuring if there's a heat source or not. If no heat is detected, the thermocouple will shut the flow of gas. Therefore, a faulty thermocouple could be shutting down the gas furnace and extinguishing the pilot light for no apparent reason.

  • A damaged or bent thermocouple will need to be bent back into shape or replaced.

  • Dirt and buildup on the thermocouple will need to be cleaned off (via sandpaper).

Pilot Tube Problems

After inspecting the thermocouple, take a look at the pilot tube. It’s possible that the walls of the tube are covered in buildup and will need to be cleared. You can easily clear the pilot tube by scraping the walls of it with a needle. You might not be able to see the inside, but scrape the walls until dirt and grime stops coming out of the tube. Once cleaned, turn your furnace back on and test to see if the pilot light stays lit.


In order for a gas furnace to work, the pilot light needs to be on — so if it’s not, roll those sleeves up! When you need a professional to inspect and repair your gas furnace, be sure to give us a call.