How to Safely Turn on a Pilot Light Furnace: A Step-by-Step Guide

Knowing how to turn on a pilot light furnace is essential for maintaining warmth in many homes that use older heating systems. Pilot lights are small flames that ignite the furnace’s burners, and understanding the proper steps to relight them ensures safety and efficient operation. This guide offers clear, detailed instructions and safety tips designed for American homeowners and renters who need to manage their gas furnaces confidently.

Step	Description	Precautions
Locate Pilot Light Assembly	Find the furnace’s pilot light area, usually behind a small access door	Ensure the furnace is off and cool before starting
Turn Off Gas Supply	Shut off the furnace gas valve completely to stop gas flow	Wait 5-10 minutes for gas to clear before proceeding
Ignite Pilot Light	Press and hold the pilot button while using a lighter or match to light the flame	Keep holding the button until the flame stays steady (15-60 seconds)
Turn Furnace On	Once pilot light is stable, turn the gas valve to the “ON” position	Monitor the pilot light to ensure it remains lit

Identifying Your Furnace Type and Pilot Light Location

Before attempting to turn on the pilot light, it is critical to identify the type of furnace in the home, as the location and design of pilot lights vary. Most older gas furnaces have a small access panel near the bottom front which conceals the pilot light assembly.

To find the pilot light: look for a small metal tube emitting a flame near the gas burner area. The access door usually swings open or slides off to give a clear view. Some modern furnaces, however, use electronic ignition systems instead of pilot lights and do not have a standing flame to light manually.

Preparation and Safety Precautions Before Relighting

Safety is paramount when handling a gas furnace. Before lighting the pilot, ensure the furnace is completely off. This means switching off the thermostat and turning off the main furnace switch, often located near the unit or on the breaker panel.

It is also important to ventilate the area if natural gas smell is present. Gas buildup could create hazardous conditions, so opening windows and doors is recommended. Wait at least 5-10 minutes after shutting off the gas valve to allow any residual gas to dissipate.

Step-by-Step Instructions to Turn on The Pilot Light

Step 1: Turn Off the Gas Supply

Locate the gas valve on the furnace—usually a small knob near the pilot assembly.

Turn it to the “OFF” position and wait for 5-10 minutes before proceeding to ensure safety.

Step 2: Access the Pilot Light Assembly

Open the furnace’s access panel carefully.

You should see the pilot light tube and a small red or black button known as the pilot or reset button.

Step 3: Ignite the Pilot Light

Using a long lighter or match, light the pilot by holding the flame near the pilot opening.

At the same time, press and hold the pilot button to allow gas flow to the pilot light.

Hold the button down for 30 to 60 seconds until the pilot flame is steady and burns brightly.

Step 4: Release the Button and Check the Flame

Slowly release the pilot button. If the pilot light goes out, repeat the ignition process.

If the pilot remains lit, proceed to the next step.

Step 5: Turn On the Furnace

Turn the gas valve knob to the “ON” position.

Close the furnace access panel.

Switch the thermostat back on and observe the furnace operation.

Recognizing a Properly Lit Pilot Light

A properly lit pilot light should have a steady, blue flame approximately one inch in length at the pilot assembly, sometimes with a small yellow tip. A weak or flickering flame, or one predominantly yellow, may indicate incomplete combustion or a clogged pilot tube. This requires professional inspection.

Troubleshooting Common Pilot Light Issues

• Pilot Light Won’t Stay Lit: Causes include a faulty thermocouple, a dirty pilot orifice, or insufficient gas pressure. The thermocouple, which senses the flame, may need adjustment or replacement.
• Difficulty Lighting Pilot: Dirt and debris can clog the pilot opening. Cleaning the area with compressed air or a soft brush can help.
• Gas Smell But No Pilot Flame: Always turn off the furnace immediately and ventilate the area. Contact a licensed HVAC technician to inspect the gas line and furnace.

Maintaining Your Pilot Light Furnace for Safety and Efficiency

Regular maintenance extends the life and efficiency of furnaces with pilot lights. Annual inspections by professionals help identify issues early and ensure safe operation. Homeowners should clean the pilot light opening periodically and check that the flame is clear and stable.

Additional recommendations include:

• Keeping the furnace area free from dust and debris
• Inspecting the thermocouple annually and replacing if worn
• Ensuring proper ventilation around the furnace to prevent buildup of combustion gases

When to Call a Professional

Attempting to light a pilot flame is straightforward, but certain signs warrant professional help:

• Repeated failure of the pilot light to stay lit
• Strong gas odors when attempting to light
• Unusual furnace noises or smells after lighting
• Irregular heating performance

Licensed HVAC contractors can perform comprehensive furnace diagnostics, repair faulty components, and conduct safe pilot light relighting.