Why Won’t The Pilot Light On My Water Heater?

The pilot light on your water heater won’t stay lit due to a potential issue with the thermocouple or a gas supply problem. A malfunctioning thermocouple fails to sense the pilot light’s heat, causing the gas valve to shut off and prevent the pilot from staying lit.

Similarly, a gas supply issue can prevent the pilot from igniting or cause it to extinguish. If you encounter this problem, it is essential to troubleshoot or seek professional assistance to ensure the proper functioning of your water heater.

Why Won'T The Pilot Light On My Water Heater?

Credit: www.waterheaterhub.com

What Is A Pilot Light, And How Does It Work?

Definition And Purpose Of A Pilot Light

A pilot light is a small, continuously burning flame that serves as an ignition source for a water heater. Its purpose is to quickly ignite the burner whenever hot water is needed in a household.

  • The pilot light is a safety feature designed to prevent gas buildup by providing a constant flame.
  • It ensures that the burner is always ready to heat water when the heater is turned on.
  • Typically located at the bottom of the heater, the pilot light is easily accessible for maintenance and troubleshooting.

The Role Of A Pilot Light In A Water Heater

The pilot light is very important for a water heater. It ensures that hot water is always available for a household. Here are its main functions:

  • Ignition: The pilot light ignites the burner in response to a thermostat signal, initiating the heating process.
  • Continuous flame: By remaining lit at all times, the pilot light provides a stable and consistent flame that can quickly ignite the burner when necessary.
  • Monitoring gas flow: In some models, the pilot light also serves as a gas valve control, monitoring the flow of gas and shutting it off if the flame goes out.
  • Safety mechanism: If the pilot light goes out unexpectedly, it triggers a safety feature that shuts off the gas supply, preventing any potential gas leaks.

Overview Of The Mechanism Behind A Pilot Light

The pilot light operates using a simple yet effective mechanism, involving the following components:

  • Thermocouple: A thermocouple is a heat-sensitive device that generates a small electric current when heated. It is located near the pilot light flame.
  • Pilot tube: This narrow tube delivers a small amount of gas to the pilot light.
  • Gas valve: The gas valve regulates the flow of gas to the pilot light and the burner.
  • Piezo igniter (optional): Some water heaters feature a piezo igniter, a small device that creates a spark to ignite the pilot light.

When the water heater is activated, the following steps occur to ignite the pilot light:

  • The gas valve opens, allowing a small amount of gas to flow through the pilot tube.
  • The piezo igniter (if present) is pressed, generating a spark that ignites the gas released by the pilot tube.
  • The pilot light’s flame then heats the thermocouple, generating an electric current that holds the gas valve open and ensures continuous gas flow to the pilot light.
  • If the pilot light goes out, the thermocouple cools down, causing the electric current to stop. This leads to the gas valve closing, preventing any gas leakage.
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Understanding how a pilot light works can help troubleshoot common issues and ensure the efficient operation of a water heater in your home.

Common Reasons For A Pilot Light Failure

The pilot light is very important for your water heater to work properly. If it goes out, you may not have hot water or your heater may not work well. Several factors can cause a pilot light to go out or fail to ignite.

Let’s take a look at some common reasons for pilot light failure:

Lack Of Gas Supply To The Pilot Light

  • Gas valve turned off: Check if the gas valve supplying the water heater is open. If not, turn it on.
  • Gas supply issue: Make sure there are no problems with the gas supply to the pilot light. A disruption in gas flow can prevent the pilot light from staying lit.

Issues With The Thermocouple Or Flame Sensor

  • Faulty thermocouple: The thermocouple is a safety device that detects the presence of a pilot flame. If it’s faulty, the gas supply to the pilot light will be shut off. Consider replacing the thermocouple.
  • Dirty or misaligned flame sensor: A dirty or misaligned flame sensor may not detect the pilot flame correctly. Clean the sensor or realign it to ensure proper functioning.

Dirty Or Clogged Pilot Light Or Burner Assembly

  • Dirt and debris buildup: Over time, the pilot light and burner assembly can accumulate dirt and debris, obstructing proper ignition. Clean the assembly using a soft brush or compressed air to remove any buildup.
  • Clogged pilot orifice: A blocked pilot orifice can prevent the release of gas required for ignition. Clean the orifice carefully using a needle or compressed air.

Problems With The Ignition System

  • Faulty igniter: If the igniter is not working correctly, it won’t generate the spark necessary to ignite the gas. Check the igniter and replace it if necessary.
  • Wiring issues: Inspect the wiring connecting the ignition system components. Loose or damaged wiring can disrupt the flow of electricity and affect ignition.

Faulty Pilot Light Or Burner Control Valve

  • Malfunctioning control valve: A faulty control valve may not supply gas to the pilot light or burner properly. Consider replacing the control valve if other troubleshooting methods fail.
  • Pilot light adjustment: The pilot light may need adjustment if it’s too weak or too strong. Refer to the manufacturer’s instructions for proper adjustment.
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Remember, if you’re uncomfortable troubleshooting or dealing with gas-related issues, it’s always best to seek professional assistance. A certified technician can diagnose and resolve the problem safely and efficiently.

Troubleshooting And Fixing A Pilot Light That Won’t Stay Lit

Having a water heater with a pilot light that won’t stay lit can be frustrating, especially when you need hot water for your daily activities. However, before rushing to call a professional, there are some troubleshooting steps you can take to try and fix the issue yourself.

In this section, we will walk you through a step-by-step guide to relighting the pilot light, as well as other troubleshooting tips to help you identify and resolve the problem.

Step-By-Step Guide To Relighting The Pilot Light

Relighting the pilot light on your water heater is often the first step in troubleshooting the issue. Follow these steps to ensure you do it correctly:

  • Locate the gas control knob: Look for the gas control knob on your water heater. It is usually located on the outside near the bottom of the unit.
  • Turn off the gas supply: Rotate the gas control knob to the “off” position and wait for about five minutes. This allows any gas that may have accumulated to dissipate.
  • Set the control knob to pilot: After waiting, turn the gas control knob to the “pilot” position. This is usually indicated by a small flame symbol.
  • Press and hold the knob: While pressing the knob down, use a long lighter or match to ignite the pilot light assembly located near the burner.
  • Continue holding and release the knob: Keep pressing and holding the control knob for about one minute after the pilot light has ignited. Then, release the knob slowly.
  • Set the control knob to on: Turn the gas control knob to the “on” position. You should hear the burner ignite, and the pilot light should stay lit.

If the pilot light goes out soon after relighting, and you’ve followed the above steps carefully, there may be underlying issues causing the problem. Let’s explore some other troubleshooting techniques to help you identify and resolve these issues.

Checking For Gas Supply And Obstruction Issues

Sometimes, a pilot light won’t stay lit due to issues related to gas supply or obstructions. Consider the following:

  • Gas supply: Ensure that the gas valve supplying your water heater’s pilot light is fully open. If it’s partially closed, the pilot light may not receive enough gas to stay lit.
  • Obstructions: Check for any obstructions blocking the pilot light or burner assembly. Dust, dirt, or debris may accumulate over time and prevent proper ignition or ventilation.

Cleaning And Maintenance Of The Pilot Light And Burner Assembly

Regular cleaning and maintenance can prevent pilot light issues and ensure proper functionality of your water heater. Consider the following:

  • Cleaning: Use a soft brush or compressed air to clean any dust or debris from the pilot light and burner assembly.
  • Ventilation: Ensure that the pilot light and burner assembly are adequately ventilated. Clear any obstructions around the area to allow for proper airflow.
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Inspecting And Replacing Faulty Components

If the pilot light continues to go out even after checking the gas supply, removing any obstructions, and doing regular maintenance, there might be faulty parts that should be examined and replaced. Consider the following:

  • Thermocouple: The thermocouple is a safety device that detects the presence of a flame to keep the gas valve open. If it’s defective, it may shut off the gas supply, causing the pilot light to go out. Inspect and replace the thermocouple if necessary.
  • Gas valve: A malfunctioning gas valve can also cause issues with the pilot light. If you suspect a faulty gas valve, consult a professional for inspection and potential replacement.

Other Tips And Tricks For Troubleshooting Pilot Light Issues

Here are some additional tips and tricks to troubleshoot pilot light issues:

  • Temperature setting: Ensure that the temperature on your water heater is not set too low. If it’s set too low, the pilot light may struggle to stay lit.
  • Drafts: Check for drafts near the water heater. Strong drafts can extinguish the pilot light. Consider installing a draft hood to prevent this issue.
  • Gas leaks: If you smell gas around the water heater, turn off the gas supply immediately and contact a professional to inspect for gas leaks.

By following these troubleshooting steps and implementing the tips mentioned, you can likely resolve the issue with your pilot light not staying lit. If you’re unsure or uncomfortable doing these tasks, it’s best to ask for help from a professional to make sure you are safe and your water heater works correctly.


Troubleshooting a pilot light that won’t stay lit on your water heater can be a frustrating experience. It is important to first determine the root cause of the issue, which could range from a faulty thermocouple to a blocked pilot tube.

Taking the necessary steps to fix the problem can save you from expensive repairs or even having to replace your water heater altogether. Always prioritize safety when handling gas appliances. If you’re unsure or uncomfortable troubleshooting on your own, it’s best to consult a professional plumber or technician.

To ensure that your water heater’s pilot light functions properly and provides hot water when you need it, follow these guidelines and seek professional help if necessary.


I am a mechanical engineer and love doing research on different home and outdoor heating options. When I am not working, I love spending time with my family and friends. I also enjoy blogging about my findings and helping others to find the best heating options for their needs.