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How to Relight a Furnace Pilot Light

by vscontent on November 10, 2017

Steps for Relighting Furnace Pilot Light

Even if you do your duty and schedule professional furnace maintenance at the beginning of each heating season, furnace problems can still develop. We’ve already discussed some of the most common furnace problems and solutions, but until now, we’ve never provided instructions for relighting your pilot light when it goes out.

If your furnace isn’t working, besides checking the thermostat, power supply, access panel and air filter, one of the first things you should look for is a properly working pilot light and burner assembly.

How to Relight Your Furnace Pilot Light

  • Check your manufacturer’s owner’s manual for specific instructions!
  • Turn the thermostat to the “off” position.
  • For older burners, manually turn off the gas using the gas valve. The valve will either be connected to the gas pipe itself or on/near the furnace (consult the user manual, usually attached to the furnace). If the gas valve has been accidentally turned off, this will explain your lack of a flame. Either way, you want to make sure the gas is completely off before attempting to relight the pilot. If you have a gas valve with the settings, “off,” “pilot,” and “on,” turn it to the “off” position.
  • After you turn off the gas, wait about 10 minutes for any excess gas to completely dissipate. Make sure the pilot gas valve is “off” for at least 5 minutes or more before turning it back on. This clears the area of any gas that could cause an explosion.
  • If you smell any gas, do not continue. You may have a leak, in which case, you should evacuate the household immediately and call your gas company and the fire department at a safe distance.
  • After airing out the chamber, turn the gas valve back on.
  • Next, open up the access panel.
  • If your furnace has a red button, press the red pilot ignitor button. Hopefully, this relights the pilot.
  • Many times, your furnace will have an ignitor button. If not, you will need to use one of those long lighters. Again, make sure you follow the manufacturer instructions for your furnace make and model.
  • Use a flashlight to find your pilot light tube.
  • If you don’t have an ignition button, find the pilot control knob. Turn the gas control knob from “off” to “pilot.”
  • Depress the pilot/gas control knob (or reset button, which is usually red) while you light the pilot with a long lighter. Make sure you know where to light!
  • Once you successfully light the pilot, keep the pilot light knob pressed down for around a minute for everything to warm up. When you release the pilot button, if the pilot stays on, you’re good.
  • If the pilot light stays lit after releasing the pilot button, switch the gas knob setting from “pilot” to “on.”
  • If the pilot light does not stay on, repeat the process from the beginning. Turn the gas off and wait at least 5 minutes for making a second attempt.
  • If you are following all of the steps correct, but the pilot still won’t stay lit, you may need to have your thermocouple adjusted or replaced. The thermocouple is a safety device that shuts off gas if the pilot light isn’t working properly.
  • Finally, close up the access panel. You can now switch your thermostat to “heat.”

Look for a Blue Flame

This is also a great time to check the furnace flame behavior and color. For furnace safety and efficiency, make sure the burner flame is  blue.

A blue flame indicates clean and efficient combustion. If there isn’t enough oxygen, your flame may be yellow or orange. Other signs of furnace flame problems include flickering flames, acrid smells, and signs of soot.

If your flame color is not blue, you aren’t just wasting money and energy on an inefficient combustion process. You are also putting your household in danger since incomplete combustion leads to more carbon monoxide (CO) released into the air.

Check your CO detectors every 30 days and learn more CO and furnace safety tips. If the CO detector goes off, evacuate the home as soon as possible and call 911.

What is a Thermocouple?

While you’re probably familiar with a pilot light, you may not be aware of the important gas furnace component known as the thermocouple. The thermocouple is a sensor that sits near the pilot light burner. Its job is to detect if there is enough heat coming from the pilot light. If there isn’t enough heat (as when the pilot light goes out or the igniter fails), the thermocouple shuts off the gas flowing into your furnace.

In this way, the thermocouple is a safety device that keeps gas from continuing to flow when there isn’t any flame to consume it. If the pilot light goes out, then you’ll need to relight it. If the pilot light will not stay lit, contact your local HVAC contractor to adjust or replace the thermocouple. You may need a new one.

Professional Furnace Service

If your heating system isn’t producing enough heat or if it’s producing no heat at all, you should call your heating contractor. Sometimes, these problems can be as simple as changing the air filter. But other time they can be the result of a more complex issue like the fan motor, the thermocouple or furnace flame combustion problems.

Contact a qualified HVAC technician if you are having any problems with your pilot light, thermocouple, carbon monoxide leaks, or any other problems with your heating system.

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For more information on furnace troubleshooting and safety, contact Pacific Heating & Cooling.

Call us at (253) 292-3995 for 24/7 service!

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