Why Did My Gas Furnace Pilot Light Go Out?

One of the most common reasons why a gas furnace stops working is because the pilot light has gone out. But why does that happen?

Pilot light failure is most common in older gas furnaces (many new gas furnaces use electronic ignitions to improve efficiency performance and reliability). Failure can happen for many reasons, including:

  1. A weak flame – Pilot light flames should burn bright blue; if yours is yellow, there is probably a leak in your system somewhere. When this happens your furnace is programmed to shut off the gas valve (for your safety), causing your pilot light to shut off.
  2. Dirt buildup – Accumulated dust and debris can clog the intake valve where the pilot light resides, making it difficult for the flame to “breath” and causing pilot light failure.
  3. A damaged thermocouple – A thermocouple is an electrical device that responds to a shift in temperature by changing its voltage output; on a gas furnace, it’s used as a safety device to cut off the supply of gas. If your thermocouple is damaged, it can cause pilot light failure and needs to be repaired by a qualified technician.
  4. A strong draft – This is the most common reason for pilot light failure, and the easiest to fix. Here’s a quick 5-step summary of how to light a pilot light on your gas furnace:
    • Step 1: Look for specific directions printed on your furnace or in your equipment’s owner’s manual. Always follow manufacturers instructions first.
    • Step 2: Find the gas valve; it’s located within the pilot light assembly and has “on,” “off,” and “pilot” settings.
    • Step 3: Turn the valve to the OFF position and wait at least 3 minutes before going on to the next step.
    • Step 4: Turn the valve to the PILOT setting and hold a lighted match next to (not inside!) the opening of the pilot light. While holding the lit match, push the reset button on the pilot control panel. Keep the button pressed until you see the pilot light return, then set the valve to the ON position.
    • Step 5: If the pilot light doesn’t stay on after several attempts, contact us for service.

Having trouble with your gas furnace or any of your other home comfort systems? Contact Carroll’s expert team today and we’ll help you sort things out!

For everything you need in home heating, trust the pros at Carroll Home Services – keeping Maryland homes warm for more than a century! Contact us to get started today!