How to relight a gas furnace: What You Need to Know

In the midst of chilly winter nights, your How to relight a gas furnace stands as a reliable source of warmth. But what happens when it suddenly goes out? Learning How to relight a gas furnace is a crucial skill for any homeowner. In this guide, we’ll walk you through the process step by step, ensuring your safety and comfort.

Understanding Your How to relight a gas furnace

What is a How to relight a gas furnace?

A How to relight a gas furnace is a heating system that utilises natural gas or propane to generate heat for your home. It operates by burning fuel within a combustion chamber and distributing the heat through ductwork to various rooms.

Components of a How to relight a gas furnace

To understand How to relight a gas furnace, it’s essential to familiarise yourself with its key components:

  • Burner: This is where the gas is ignited to produce heat.
  • Pilot light: A small flame that ignites the burner when the furnace is turned on.
  • Thermocouple: A safety device that detects whether the pilot light is lit.
  • Gas valve: Controls the flow of gas to the burner and pilot light.

Signs your How to relight a gas furnace needs relighting

Several indicators suggest that your How to relight a gas furnace may need relighting:

  • Cold air: If your furnace is blowing cold air instead of warm air, it could indicate a problem with the pilot light.
  • Unusual odours: A distinct smell of gas near the furnace may signal a pilot light or gas supply issue.
  • Visible pilot light: If you can’t see the pilot light through the furnace window, it may have gone out.

Safety Precautions Before Relighting

Before attempting to relight your How to relight a gas furnace, prioritise safety measures:

Turn off the How to relight a gas furnace supply

Locate the How to relight a gas furnace shut-off valve near your furnace and turn it to the “off” position. This prevents gas from flowing while you work on the furnace.


Ensure proper ventilation in the area surrounding the furnace. Open windows or doors to allow fresh air to circulate and prevent the buildup of gas fumes.

Checking for How to relight a gas furnace leaks

Use a How to relight a gas furnace leak detector or a solution of soap and water to check for gas leaks around the furnace and gas connections. If you detect a leak, do not attempt to relight the furnace and contact a professional immediately.

Gathering necessary tools

Before you begin, gather the following tools:

  • Long-reach lighter or matches
  • Flashlight (if working in a dimly lit area)

Steps to Relight a How to relight a gas furnace

Locating the pilot light

How to relight a gas furnace The location of the pilot light may vary depending on your furnace model. Consult your furnace manual or look for a small access panel near the base of the furnace.

Preparing How to relight a gas furnace

Clear any clutter or debris around the furnace to ensure a safe working environment. Make sure there are no flammable materials nearby.

Turning the gas valve to pilot

Locate the gas valve near the pilot light and turn it to the “pilot” position. Hold the valve in this position to allow gas to flow to the pilot light.

Lighting the pilot light

Using a long-reach lighter or matches, carefully ignite the pilot light. Hold the flame near the pilot burner while pressing the reset button or igniter switch.

Adjusting the flame

Once the pilot light is lit, How to relight a gas furnace adjust the flame using the gas valve control. The flame should burn steadily with a blue colour and no sputtering.

Testing the furnace

After successfully relighting the pilot light, turn the gas valve back to the “on” position and set the thermostat to a higher temperature. Listen for the sound of the burner igniting and feel for warm air coming from the vents.

Troubleshooting Common Issues

Pilot light keeps going out

If the How to relight a gas furnace pilot light repeatedly goes out after relighting, it may indicate a faulty thermocouple or a draft near the furnace. Check for drafts and consider replacing the thermocouple if necessary.

Weak or yellow pilot flame

A weak or yellow pilot flame could be caused by a dirty burner or a lack of oxygen. Clean the burner and ensure proper ventilation around the furnace to resolve this issue.

Furnace still not working

If relighting the How to relight a gas furnace pilot light doesn’t solve the problem, there may be deeper issues with your furnace, such as a faulty gas valve or ignition system. In such cases, it’s best to contact a professional HVAC technician for assistance.

When to call a professional

If you’re unsure about relighting your How to relight a gas furnace or if you encounter any safety concerns during the process, don’t hesitate to seek help from a qualified HVAC technician. They have the expertise and equipment to diagnose and repair furnace issues safely.

Maintenance Tips for Preventing Future Issues

Regular inspections

Schedule annual maintenance inspections with a professional HVAC technician to ensure your furnace operates efficiently and safely.

Replacing outdated components

Consider replacing outdated components such as the thermocouple or How to relight a gas furnace valve to prevent future breakdowns and ensure optimal furnace performance.

Cleaning and lubricating

Perform regular cleaning and lubrication of moving parts to extend the lifespan of your furnace and prevent premature wear and tear.


Knowing How to relight a gas furnace is an essential skill for homeowners. By following these steps and safety precautions, you can effectively troubleshoot common furnace issues and maintain a warm and comfortable home during the colder months. Remember to prioritise safety at all times and seek professional assistance when needed. Stay warm and cosy!