A Complete Guide on How to Re-light Your Furnace Pilot Light Safely

Use this guide to learn how to re-light your furnace pilot light safely as well as additional reasons why your gas furnace may not be igniting.

Re-lighting a furnace pilot light is a very simple process and only requires one item; a long match or lighter to safely relight the pilot flame. The length of the match is crucial since it’s not advisable to stand very close to the flame when it catches. If the furnace area is dimly lit, you should use a flashlight to help you find the furnace pilot light. 

Before you do anything, you first have to remove the access door. This is a straightforward task; with most furnaces, you can remove the access door without any tools. However, if screws secure the access door, you may need 1-2 minutes to loosen and remove the door. Ensure the screws are a safe place since you can easily misplace them in the process. Some furnaces have re-lighting instructions at the back of the access door but if yours doesn’t, use the following instructions:

Step One: Find the Pilot Light Assembly and its Reset Switch 

The furnace’s pilot light is usually positioned at the bottom of the unit by a valve control knob. The valve control is typically marked with three settings:

  1. Pilot
  2. On
  3. Off 

In addition, you will also find the reset switch. The reset switch is painted red and is found beside the gas valve control knob. 

The gas control knob can be used as a reset switch for furnaces without a separate reset switch, just push it down. If you can’t easily find the pilot light and reset switch, look in your owner’s manual for the manufacturer’s instructions or a diagram that indicates its location. If you can’t find the physical manual, check the manufacturer’s website for a digital copy. 

Step Two: Turn the Valve Control Knob to the Off Position

Turn the knob to the off position to stop the flow of gas. 

Step Three: WAIT

Wait at least five minutes to pass from turning off the pilot light before attempting to relight it. This lets the remaining gas dissipate from the chamber to reduce the risk of flare-ups when you finally spark your lighter.

Step Four: Relight the Pilot Light

Turn the knob to ‘Pilot’, letting the gas flow to the pilot. Light a lighter or long match, bringing the flame close to the pilot light opening as you press and hold down the reset button. Keep the reset switch depressed until the pilot light is burning steadily. Then, release the button. If your furnace doesn’t have a reset button, press down the control knob to serve as the same heating process.

Step Five: Control Gas Amount Through the System

After the pilot light is lit, now turn the control knob to ‘On’. This ensures that the right amount of gas flows through the furnace to generate appropriate heat.

If this is your first time relighting a pilot light, you may not be successful on the first try. In this case, wait for a few minutes before you repeat the steps. During the second try, make sure you push and hold down the reset button longer. Holding longer increases the chances of lighting the flame to stay lit.

If your furnace is still not igniting, then there may be other issues that need to be identified.

Furnace Not Igniting: What May Be The Reason?

Here are the five main reasons for a furnace not igniting:

Thermostat Errors

A furnace may fail to ignite due to errors in the thermostat setting. First, be sure a thermostat is set to heat at a lower temperature than in your home. If it fails to turn on, check error codes. Some modern electronic thermostats will always display error codes to show where issues are. The case might be more than a simple thermostat issue; therefore, you may need a furnace repair.

Gas Line Issues

First, be sure the gas supply is on by examining the external shut-off valve. Additionally, you can confirm that the gas supply is on by running another gas appliance such as an oven or stove. If other gas appliances are working, you should make sure that the furnace gas supply is clear and open. If there is a partial or complete blockage, the furnace might lack adequate gas to ignite. For such issues, seeking professional assistance is inevitable.

Filter Issues

Your furnace may also fail to turn on due to filter issues. One of the effective ways of fixing a broken furnace is to change its air filter. Clogged filters can ultimately impair a furnace by interfering with gas flow. If a furnace fails to turn on, check if its filter is clean and recently changed. Suppose the issue isn’t sorted; you may need professional heating and cooling assistance to clean the ducts.

Faulty Ignition Censors

Faulty ignition sensors are the most common cause of furnace ignition failure. In most cases, furnaces are heard clicking without firing up. Fortunately, a faulty or dirty pilot ignition sensor is easy to fix. You can even clean and fix it yourself in the following steps;

  • First, turn off the gas supply, then remove the panel to locate the sensor, which is located near the furnace’s burners.
  • Suppose the sensor is dirty; remove it using a screwdriver. Clean it carefully to avoid breakages.
  • Replace and screw back the sensor, then replace the front panel.
  • Put on the gas and put the furnace on

Note that if this is the first time you are igniting your furnace, then know that it might take time depending on the length of the gas line and how much time fuel takes to reach the pilot light. Patience is very crucial since, at times, it may take a few minutes to light the pilot. 

Unit Issues

At times, the unit could also be the issue. You may accidentally turn off the switch inside the furnace; thus, check to be sure it is on. Also, check the breaker to make sure the power to the furnace hasn’t been tripped. If tripped, flip the breaker back on.

Final Thoughts

In summary, re-lighting your furnace is five basic steps anyone can follow. For instructions based on your model look in your owner’s manual for the manufacturer’s instructions or a diagram that indicates exactly how to do this. If you can’t find the physical manual, check the manufacturer’s website for a digital copy. For more information about furnaces, visit this website.

If you are still uncomfortable or having issues relighting your furnace, call a qualified HVAC system technician, like Patriot Air, for help. Regardless of how big or troublesome the problem may look, a qualified and experienced air conditioner and heating repair specialist will have a lasting solution.