Why my Water Heater Pilot Light Goes Out? 
Troubleshooting and Repairing Tips

If you rely on hot water for daily activities such as showering and washing dishes, a pilot light outage can be a major inconvenience. This is a common issue that can cause your gas-fired water heater to stop providing hot water.

Understanding why the water heater pilot light goes out and how to troubleshoot and resolve the problem is essential if you want to ensure that your water heater is working efficiently and effectively to deliver hot water whenever you need it.

Things to consider when your water heater pilot light goes out

What is a water heater pilot light and how it works?

A water heater pilot light is a small gas flame that is always burning near the bottom of a gas-fired water heater tank. It ignites the gas burner when the water temperature drops below the set level, and is controlled by a gas control valve.

A thermocouple, located near the opening of the combustion chamber, senses if the pilot light goes out and shuts off the gas supply to prevent gas leaks and fire hazards.

Some newer models of water heaters use electronic ignition systems instead of pilot lights for improved energy efficiency.

How do I know if my pilot light is out on my water heater?

You can tell if your pilot light is out on your water heater by checking the indicator. The location of the indicator will vary depending on the make and model of your water heater. If the pilot light is out, the indicator will not be lit.

You can also visually inspect the pilot light through the viewing window, which is typically located near the control valve. If the pilot is on, you should see a small blue flame burning steadily. If the flame is out, you will not see any flame through the sight glass.

Additionally, if you notice that your water is not heating up or you are running out of hot water quickly, it may be a sign that the pilot light is out.

In any case, it is important to follow the manufacturer's instructions for relighting the pilot light and to exercise caution to ensure your safety.

The main reasons why the water heater pilot light goes out and how to repair it

To avoid problems, sufficient air must be supplied to the combustion chamber for both the pilot light and the main burner, especially with new FVIR technology that cannot tolerate a contaminated environment.

Regular maintenance of the burner assembly, including cleaning the flame arrestor from dirt, dust, and lint, is necessary for gas water heaters. The area where the gas control valve is located and the opening for the air intake and venting must not be restricted.

Our focus here is to explain how improper venting affects normal pilot light performance, the problems it causes, and why your water heater pilot light goes out.

A correctly sized and properly run venting system is also essential for regular water heater performance and efficiency.

We will explore the following several reasons why your water heater pilot light goes out and how improper venting, for example, can cause improper water heating operation:

• Capping
• High ambient temperature
• Decompression
• Pilot lights, but goes out when button released

Pilot light goes out due to capping problem

Poorly designed and installed venting systems and outside weather conditions can cause "capping" and force the flue to stall. This occurs when the downward force of the air is equal to or greater than the draft in the vent, mainly due to high wind conditions.

The natural draft inside the flue will not be sufficient to allow products of combustion from the pilot flame to rise; instead, they will be pushed down, causing all the oxygen needed for gas combustion to be used up.

To prevent the pilot light from extinguishing, a vent termination must have an extension of at least two feet above the roof to provide a necessary difference in pressure and allow for a natural draft.

Pilot light goes out due to high ambient temperature

The most common scenario for pilot outage occurs when a water heater is installed in spaces like the attic or garage, where ventilation is an issue and there is an insufficient amount of incoming fresh air.

Water heater installation in the attic is especially problematic due to the high temperature of the surrounding air, poor ventilation, and low traffic. Poor ventilation leads to a lack of incoming fresh air for combustion, resulting in improper gas combustion.

How can you recognize improper gas combustion?

You can observe what is happening inside the combustion chamber of your water heater using the sight window on the unit, if there is one. The flame on the main burner changes color from light blue to yellow and red. This condition will also result in a change in the flame pattern, where it will first light smoothly and then you will see a luminous burner flame that will eventually flatten out.

If the air surrounding the water heater is hotter than the tank's set temperature during the summer months, the thermostat won't open the gas valve to light the main burner.

The heat produced by the pilot flame is not enough to create the natural draft, so all the oxygen burns up, and the pilot light extinguishes.

Moreover, if there is poor ventilation, the hot air tends to rise, and the combustion air from the attic doesn't come down to provide oxygen to the burner, resulting in a pilot outage.

What to do if the pilot light goes out due to decompression

Decompression occurs when the inside air pressure drops below the outside pressure. Instead of the products of combustion flowing from the water heater out, the higher outside air pressure pushes the flue gases down, causing negative pressure. This, in turn, prevents fresh air from reaching the combustion chamber and pilot light, leading to the pilot light going out due to a lack of oxygen and a lack of natural draft in the flue pipe.

These three cases of improper water heater installation or venting serve as good examples of why it's important to avoid installation in areas that are too small or closed rooms (such as an attic) where there is insufficient air movement. Follow the codes for venting, ensure that air provisions meet requirements and that there is a sufficient amount of air, and take note of what is needed when installing two or more gas appliances in the same room.

Insufficient air supply can cause the recirculation of combustion products, which can contaminate the surrounding air and become hazardous to life. It can also lead to improper gas combustion, resulting in carboning or sooting of the combustion chamber, burners, and flue tubes.

The pilot lights, but goes out when a button is released

• Ensure that the gas control button, which lights the pilot, is fully depressed and held down for at least 20 seconds.
• Verify that the gas type used matches specifications found in the manual or rating sticker on your water heater.
• Check all connections of the pilot circuit.
• Check the thermocouple and if it is in full contact with the pilot light.
• If you are using power vent tankless models, check the sensors in the draft diverter.
• Low or no gas pressure.
• Dirt in gas lines.
• The pilot line or orifice got clogged.

If the pilot light goes out and you smell gas leaking, turn the gas valve to OFF. If the gas smell is still present after turning the unit OFF and it doesn't dissipate, turn off the main gas valve, call the gas utility company to check, and wait for them outside.

Beyond improper venting: What else can cause water heater pilot light issues?

1. Lack of gas supply: If there is no gas flowing to your water heater, the pilot light will not stay lit. Make sure the gas supply valve is turned on and that the gas line is properly connected.
2. Dirty pilot tube: If the pilot tube is clogged with debris, the pilot light may not be able to stay on. Try cleaning the pilot tube with a small wire brush.
3. Faulty thermocouple: The thermocouple is a safety device that shuts off the gas supply if the pilot light goes out. If the thermocouple is faulty, it may be causing the pilot light to go out. Replace the thermocouple if necessary.
4. Bad gas control valve: If the gas control valve is faulty, it may not be supplying enough gas to keep the pilot light lit. Replace the gas control valve if necessary.

Is it dangerous if the pilot light goes out on the water heater?

If the pilot light goes out on a gas water heater, it can be dangerous if not addressed promptly. The pilot light is responsible for igniting the gas that heats the water in the tank. If the pilot light goes out, gas can continue to flow, which can create a hazardous situation.

Gas is odorless, so a safety feature is added to make it detectable. This is done by adding an odorant, which smells like rotten eggs, to the gas. If you smell this odor or suspect a gas leak, immediately turn off the gas supply to the water heater and contact a professional plumber or gas company for assistance.

In addition to the potential safety hazards, a pilot light that goes out can also result in a lack of hot water, which can be inconvenient. If you're experiencing issues with your water heater pilot light, it's important to address the problem promptly to ensure safe and efficient operation of your water heater.

How to relight a water heater pilot after fixing it

Here are the simplified steps to relight a gas water heater using a piezo igniter:

1. Turn off the gas supply valve and wait for 5 minutes.
2. Locate the pilot light assembly and turn the temperature dial to "Pilot".
3. Press and hold the control knob or button, and use the piezo igniter to ignite the pilot light.
4. Hold the control knob or button for 30 seconds after the pilot light is lit.
5. Release the control knob or button and turn the temperature dial back to the desired setting.
6. Turn the gas supply valve back on.

Remember to check for gas leaks and contact a professional if you are unsure or detect gas.

Conclusion

In conclusion, a water heater pilot light outage is a common issue that can be resolved with a bit of knowledge and some DIY effort.

By understanding the potential causes and following the troubleshooting steps, you can identify the issue and take the necessary steps to repair or replace the faulty components.

Whether the problem is related to improper venting, a faulty thermocouple, or a malfunctioning gas valve, taking prompt action is key to ensuring that you have a reliable supply of hot water for all of your daily activities.

With the right tools, knowledge, and support, you can quickly resolve any pilot light issues and enjoy the comfort and convenience of hot water whenever you need it.