Why Does The Water Heater Pilot Light Keeps Going Out?

Posted by: Mas Broto
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Why Does The Water Heater Pilot Light Keeps Going Out

When the pilot light on your water heater keeps going out, it’s inconvenient and frustrating. Even though it is a small part, if it doesn’t work, the whole unit is useless. Here are some reasons why your water heater pilot light keeps going out and ways to fix the problem.

No hot water is the one thing that everyone hates. This can be very annoying, not only when you want to take a shower but also when you need hot water for other things. You don’t have to put your day on hold because of a pilot light that doesn’t work. Find out what a pilot light is and why it’s so important to your comfort by reading on.

What’s a Water Heater’s Pilot Light?

The pilot light on a water heater is a part that keeps a flame going all the time. This part’s job is to light the burner. When you turn on your water heater, gas comes out of the main burner and is lit by the pilot light. This heats the water. As this heat warms the main burner, it heats and moves the water inside your unit.

Reasons Why Your Water Heater Pilot Light Keeps Going Out

There are a few reasons why the water heater pilot light keeps going out, but the main one is a broken thermocouple.

1. Issues with Thermocouples

thermocouple in a gas water heater

The thermocouple controls the flow of gas to the gas burner. It is an important safety feature of a water heater. It basically looks for a burning flame and shuts off the gas flow when there isn’t one. This keeps gas from building up. If you want to light the pilot light on your own water heater, you have to hold the “Pilot” button to control the gas flow while you light it. But when you let go of the button, the thermocouple takes over and uses its flame sensor to figure out if the gas should be flowing or not.

There are a lot of problems that can happen with water heater thermocouples. You can look around to find out what the problem is and if you can fix it yourself. If you take off the access panel over the pilot light and look at the gas burner, you should be able to see a cylinder-shaped metal piece next to the gas valve and igniter. That is the thermocouple, and to figure out what’s wrong, you can do a few things.

Common thermocouple problems:

  1. Dirty
    If you can light your pilot light, but the pilot light on your water heater keeps going out, there are many things that could be wrong. One of them is a thermocouple that is dirty. If your water heater doesn’t light, check the pilot light. See if the thermocouple is dirty by looking at it. If so, turn off the gas and let the thermocouple cool down. Then, use fine sandpaper to gently clean it. Then turn back on the gas and try to light the pilot.
  2. Bent
    If your gas water heater doesn’t stay lit, you may find that the thermocouple has been bent if you check it. So, the pilot light won’t be able to heat it. If you do this, the thermocouple will shut off the gas supply, and your water heater won’t light. Bend the thermocouple, so it is closer to the pilot light to keep your water heater from going out.
  3. Damaged
    If none of these methods work, your thermocouple may be broken and need to be fixed or replaced.

2. Dirty Pilot Tube

Dirt or soot can build up in the water heater pilot light, making the flame weak or stopping it from lighting at all. If your pilot burner has a weak, flickering yellow flame instead of a strong, blue flame that’s no more than half an inch high, it’s most likely because the burner is dirty. When the pilot tube has cooled, you can gently clean it with a needle to get rid of any clogs, but if the problem keeps coming back, you should call a professional technician.

3. Poor Location

If your water heater is in a small room with little or no airflow, like a closet or a basement with no windows, the flame of your pilot light may be struggling to stay lit because it doesn’t have enough oxygen to burn. If the chamber where the gas burner sits at the bottom of the water heater isn’t sealed well, a strong draft or a change in the air pressure outside could be blowing out the pilot light all the time.

Check the inside and outside of the base of the water heater to make sure there are no cracks or panels that aren’t properly connected. Also, check to see where the nearest air vent is and make sure it isn’t blocked in a way that would cause a downdraft toward the water heater.

4. A Bad Gas Valve

Your gas water heater will turn off if the pilot light or burners stop getting gas because the gas valve or its parts inside are broken. If you have already ruled out problems with the pilot light or thermocouple, the gas valve on your water heater is probably the problem. Your HVAC technician is the best person to fix or change the gas valve.


There are many reasons why the water heater pilot light won’t light or keeps going out. If you are having trouble identifying the problems, it’s always best to call a professional to fully check out the water heater.

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Mas Broto

Have been in the heating and air conditioning (HVAC) industry for over 20 years. He is person that will grow and thrive to learn more about the HVAC industry throughout his career. Mas Broto is also a blogger, who's dedicated to bringing you the best knowledge to get ahead in the game of life.

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