Understanding Why A Pilot Light Won’t Stay Lit

Few furnace problems are as frustrating as a pilot light that goes out over and over–especially because this problem seems like it should be so easy to fix. The good news is that, with the right knowledge, the problem may indeed be a simple one. If you would like to learn more about troubleshooting a pilot light that won’t stay lit, read on

Pilot Light Mechanics

Your furnace’s pilot light is located between the two gates on the main gas valve. When the pilot is running, a nearby thermocouple senses the heat and keeps the first gate open, thus allowing the pilot to remain lit. When the pilot light goes out, the thermocouple cools back off and sends a signal to the gas valve to close the first gate. This keeps raw gas from flowing out into the air of your home.

Button Override

On the gas valve is a button that must be pressed when relighting the pilot light. This button simply acts as a manual override of the first valve gate. In other words, when you depress the button, gas begins flowing to the pilot, allowing you to light it with a long match or lighter.

Here is where problems often occur. If you let go of the pilot button too quickly, you may find that the pilot sputters and goes out. This is because the thermocouple has not had enough time to heat up. Unless it reaches a certain temperature threshold, it will not send the signal to keep the valve gate open. Next time you try relighting the pilot, be sure to keep the button depressed for several seconds while the thermocouple heats up.

For more information about troubleshooting a stubborn pilot light, please don’t hesitate to contact the experts at Green Leaf A/C and Heating.