How to Light a Pilot on a Water Heater Safely: DIY Tips

Learning how to light a pilot on a water heater is an essential DIY skill for homeowners. Whether you own a Rheem, Bradford White, AO Smith, or another brand, mastering this process can save time and money, and enhance your comfort.

From how it works to safely relighting your water heater’s pilot light, this guide provides clear, actionable steps tailored to Honeywell, Rodgers-White, and Robertshaw gas control valves.

Note: Every gas water heater comes with a label detailing how to light the pilot on the unit. If you can’t find the instructions, don’t worry—this guide covers everything you need to know. Knowing how to do it is essential when replacing parts like the pilot assembly or after gas supply interruptions.

How Does the Pilot Light Work?

The pilot light assembly consists of key components like the thermocouple, burner, and igniter.

When you press the igniter button, it generates a piezoelectric spark that ignites the pilot flame. This flame serves a critical purpose: it heats the thermocouple, which in turn generates a small electrical current to keep the gas valve open, ensuring a steady flow of gas to the burner.

Once the pilot is lit, it functions as the ignition source for the main burner. When the thermostat signals a need for heat, the main burner is activated by this small flame to heat the water in the tank. Without a properly functioning pilot light, the water heater cannot operate effectively. If you experience issues or need detailed troubleshooting steps, consult the manufacturer’s manual or explore reputable DIY guides for expert advice.

Safety Tips for DIYers:

• Follow Manufacturer’s Instructions: Always consult the specific instructions for your gas model. These can typically be found on the heater or in the user manual.
• Ensure the Water Heater is Full: Before lighting the pilot, confirm that the water heater tank is completely filled with water to avoid damaging the unit.
• Purge the Gas Line: Clear out any air in the gas line by following the instructions carefully. Skipping this step can make ignition difficult.
• Avoid Hand Lighting: Never attempt to light the flame manually. Use only the built-in ignition system for safety.
• No Tools Needed: Always turn the gas control knob with your hand. If it’s stuck, stop and call a professional rather than forcing it with tools.

Lighting a Pilot Light on a Honeywell Gas Control Valve

The Honeywell gas control valve, found on many gas models, is DIY-friendly and offers a simple way to control the gas supply and water temperature. Here’s how to light a pilot on a water heater with this valve:

• Turn Off the Gas: Rotate the gas control/thermostat knob to the OFF position. Wait at least 5 minutes to ensure any residual gas has cleared from the combustion chamber.
• Vent the Area: Remove the water heater’s outer door to allow any trapped gas to escape, ensuring a safe relighting process.
• Set to Pilot: Turn the gas control knob to the Pilot position. This prepares the system to send gas only to the pilot burner.
• Ignite the Pilot: Push and hold the gas control knob to release gas to the pilot burner. Press the piezo igniter button firmly. If it doesn’t ignite on the first attempt, try again a few times.
• Secure the Flame: Once the flame ignites, keep the control knob pressed for at least 30 seconds. This allows the thermocouple to heat up and generate electricity to hold the gas valve open.
• Verify and Turn On: Release the knob slowly. If the pilot stays lit, turn the control knob to the ON position and set the thermostat to your desired temperature. The recommended setting (around 120 F)) is usually marked on the dial.
• Retry If Necessary: If the pilot doesn’t stay lit, repeat the steps. Be sure to vent the combustion chamber before each attempt.

Lighting a Pilot Light on Robertshaw and Rodgers-White Gas Control Valves

These valves operate similarly to Honeywell’s and are designed for DIY enthusiasts who prefer to manage minor repairs and maintenance themselves.

• Set Thermostat to Lowest Setting: Before starting, turn the thermostat dial to its lowest position to avoid accidental activation of the main burner.
• Turn Off the Gas: Rotate the control knob to the OFF position. If the knob is difficult to turn, press it down slightly to release the lock mechanism. Wait several minutes to allow any lingering gas to dissipate.
• Remove the Outer Door: Open the outer door of the water heater to ventilate the area and provide access to the pilot assembly.
• Set to Pilot: Turn the gas control knob to the Pilot position, which ensures gas flows only to the pilot burner.
• Press and Hold the Control Knob: Depress the knob or pilot set button to release gas to the pilot burner.
• Ignite the Pilot Flame: While holding the knob, press the piezo igniter until you hear a distinct “click” or see the flame through the sight glass window.
• Secure the Flame: Hold the knob for 60 seconds after ignition to allow the thermocouple to heat sufficiently and keep the gas valve open.
• Test and Adjust: Release the knob and confirm the pilot stays lit. Turn the gas control knob to the ON position and adjust the thermostat to your desired temperature setting.

Understanding and Managing Your Water Heater Pilot Light

Below, you’ll find answers to common questions about your water heater pilot light, along with tips to help ensure it stays lit.

Is a Water Heater Pilot Light Always On?

Yes, the pilot light on traditional gas water heaters is designed to stay on continuously. It functions as a small, steady flame that ignites the main burner when the thermostat signals a need for heat. If your water heater uses electronic ignition instead, it may not have a constant flame.

What Does a Pilot Flame Look Like?

The pilot light is a small blue flame visible through the sight glass on your water heater. It’s usually located near the base of the tank within the combustion chamber. A properly functioning pilot light should be a steady, clean flame—typically blue with a yellow tip. If it appears weak or flickers, it may require adjustment.

Can a Pilot Light Go Out on a Water Heater?

Yes, it can go out due to several reasons, such as a draft, gas supply interruption, or a dirty thermocouple. If this happens, your water heater won’t function, as this small flame is essential for igniting the main burner. Knowing how to relight the pilot safely is a valuable DIY skill for homeowners.

Why Does the Pilot Light on a Water Heater Go Out?

Here are some of the reasons (see more here):

• Drafts: Strong air currents near the water heater can extinguish the flame.
• Dirty Thermocouple: A soiled or worn-out thermocouple may fail to sense the flame, shutting off the gas supply as a safety measure.
• Gas Supply Issues: Intermittent gas flow or low pressure can cause the flame to extinguish.
• Clogged Burner: Dirt or debris in the pilot assembly can prevent the flame from staying lit.

DIY Tip: Ensuring Proper Operation

Regular maintenance is key to ensuring your pilot light operates properly. Clean the assembly and thermocouple periodically and keep the area around your water heater free of drafts and debris. If it goes out, consult your water heater’s manual for relighting instructions, and make sure the gas supply is uninterrupted.

By understanding how the pilot light works and what can cause it to go out, you’ll be better prepared to manage your water heater effectively.

Conclusion

Now that you know how to light a pilot on a gas water heater, you’re equipped to handle this common DIY task with confidence. Whether working with a Honeywell, Robertshaw, or Rodgers-White valve, following these detailed steps ensures a safe and successful process. Always prioritize safety and consult your water heater’s instructions.

If you’re ever in doubt, reach out to a professional technician for assistance. By mastering this skill, you can save money, avoid downtime, and ensure your water heater operates efficiently.