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How to Light a Furnace Pilot Light

furnace pilot light

How to Light a Furnace Pilot Light

Even in Texas, winters can get pretty chilly. Before cold weather sets in, you need to do a once-over to make sure your heating system is ready to take on the coldest temps of the year. Check the pilot light on your furnace. The furnace pilot light might just be one of the most important parts of your heating system. Without it, your gas furnace won’t ignite no matter how high you set the thermostat. Luckily, it’s pretty easy to relight your pilot light in most cases. With the following information, you’ll be ready for just about anything winter throws at you.

Understanding the Pilot Light

The furnace pilot light is a small burner that’s used to keep the larger furnace burners going. It’s dependent on the thermocouple, which opens the gas valve. The thermocouple is a metal case that contains metal wires welded together. One end of the thermocouple is attached to the pilot valve body while the other end, which contains the sensor, is in the hottest part of the flame. Once the light gets hot enough, the thermocouple will send an electric signal to the gas valve, which opens. When the pilot light goes out, the thermocouple will cool off, and the valve will close.

Lighting the Pilot Light

Pilot lights go out for a variety of reasons, but in most cases, it’s a simple enough job to light them again. First, don’t be in a hurry when it comes to relighting the pilot flame. When it comes to gas, you’re better off taking your time and reading the instructions first. Your furnace should have a label that details the best way to light the pilot. If you follow the furnace-specific instructions, you should be able to get the pilot light going again without too much difficulty.

Need some help?

Watch John, one of our HVAC technicians, explain how to ignite a pilot light in this short video.

(Keep in mind that your water heater might require a slightly different process, so be sure to read the instructions.)

If the label is gone or too dark or old to read easily, then you’ll need a Plan B.

Plan B

Start by locating the pilot light. Your furnace should have a switch that says “on,” “off” and “pilot.” It should have another switch or button labeled “reset.” These will typically be near the bottom of the furnace. Turn the switch off, and wait at least five minutes to allow any remaining gas to dissipate.

Next, turn the switch to “pilot,” and hold down the reset button. Use a long lighter to light the furnace pilot light. Once it’s got a flame, which can take about 30 seconds, you can release the reset button. If it doesn’t light the first time, wait a few minutes and try again, this time holding the reset button down for 45 to 60 seconds. Your flame should be blue-green with a bit of yellow at the tip. This means it’s getting hot enough to heat the thermocouple properly.

Once the furnace pilot light has a steady flame, you can turn the switch on and adjust the thermostat to the desired temperature.

Furnace Ignitor

Newer furnaces typically do not have pilot lights but instead have an electronic ignition. You cannot light a furnace ignitor the same way that you light a pilot light. However, you can reset it. Turn the electric ignition off, and then push the reset button. Check the owner’s manual for specific information on resetting your model.

If you’ve tried to light the furnace pilot light at least twice and been unsuccessful, it’s time to call the professionals. Because gas can be extremely dangerous, furnace repairs are not a DIY project. Contact us today to speak to one of our experts or to schedule your appointment.