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pilot light water heater

If you own a gas water heater, than chances are at some point your pilot light has gone out. The pilot light is an important part of a gas water heater and when its not lit, or functioning properly, your “hot” water will run cold. Learning to do some simple troubleshooting and how to light the pilot can save you some money by fixing the issue yourself versus calling a professional plumber.

Although, electronic ignitions are common on newer gas water heaters, many older heaters still use pilot lights. If your water heater uses a pilot light, it’s not uncommon to have issues. This article will help you troubleshoot the problem and determine what to do next.


What is a Pilot Light? What Does it Do?

Gas and propane fueled water heaters use a small flame to ignite the burner. This small flame is called a pilot light and it stays lit at all times. When the water heater needs to heat the water within the tank, it ignites the gas burner with the help of the pilot light. 

Think of the pilot light like a match. You might strike a match to light a fire or gas stove. But if you don’t have a match, you won’t be able to start a fire or fire-up your gas stove. The same is true with a pilot light. If the pilot light goes out, your water heater won’t be able to ignite the gas burner and therefore, won’t be able to heat the water. In fact, often the first clue your pilot light is out is the discovery that you don’t have hot water.

But once the pilot light is relit, the water heater is able to ignite the gas burner and can begin to heat the water again.

Signs Your Pilot Light Has Gone Out

There are three primary indications that your pilot light has gone out:

No Hot Water – If your hot water is no longer hot, there’s a good chance that your pilot light has gone out. There are, of course, other reasons why you have no hot water, so if the problem is not the pilot light you’ll need to do a little more troubleshooting.

Gas Control Valve Indicator – You may notice an error message or a blinking light on the gas control valve. Sometimes the indicator light changes colors to alert you to a problem. Look for a sticker on the side of the tank which describes what the indicator message means. The pilot light being out is always one of the issues listed.

No Flame – If you conduct a visual inspection and you can’t see a flame, then your pilot light is definitely out. See below to learn how:

How to Check if Your Pilot Light is Out

Visually checking for a flame is worth doing, even if your gas control valve indicates there’s an issue with the pilot light. You’ll typically find the water heater’s burner chamber door below the gas control valve at the bottom of the unit.

Depending upon your water heater, you’ll need to either remove the door or open it in order to view the burner chamber and the pilot light tube. If you see a flame, the problem isn’t with the pilot light. However, if you don’t, then the pilot light has gone out.

What Causes a Pilot Light to Go Out?

There are a number of different reasons that a pilot light goes out. Here are a few of the more common causes:

Change in Gas Pressure – It’s not uncommon for the pilot light to go out if there’s a natural change in gas pressure. Although it won’t happen often, it does occur and relighting the pilot typically resolves the problem. However, if the pilot light continues to go out, something else is going on.

Thermocouple – The thermocouple’s primary role is to act as a safety device by shutting down the gas valve should the pilot light go out. This prevents the flow of gas to the chamber. If your heater’s thermocouple begins to malfunction, is bent or dirty, it may be shutting down the pilot light even if everything else is functioning properly. You can learn more about troubleshooting a thermocouple in this article.

Draft – If your water heater’s combustion chamber isn’t sealed, it’s possible that a burst of air will extinguish the pilot light. Since the pilot light is simply a small flame, it can easily be blown out if the heater is located in a drafty area.

Lack of Combustible Air – Gas appliances, such as water heaters, require air in order to safely operate. If your unit is located in a closet or other area where it will not have access to the air it needs for combustion, the pilot light may not stay lit. If this is your situation, we highly recommend contacting a professional to help you troubleshoot the problem. This situation has the potential to be dangerous, as it could lead to a build-up of carbon monoxide in your home.

Is it Dangerous if the Water Heater’s Pilot Light Goes Out?

In most cases, it isn’t dangerous when the water heater pilot light is extinguished. This is because modern gas-fueled water heaters feature valves that automatically close the supply of gas when the pilot light goes out. 

This is a very important safety feature, and if your water heater didn’t do this, then you would have a natural or propane gas leak on your hands, which is a serious explosion hazard. That being said, this situation can be dangerous when the water heater is in an enclosed space.

For example, if your pilot light has gone out due to a lack of combustible air, it can create a build-up of carbon monoxide in the area. Carbon Monoxide is extremely dangerous and may even cause death.

Regardless of where your water heater is located, we highly recommend purchasing a carbon monoxide detector. They are inexpensive and can be positioned near your water heater. Should the carbon monoxide levels rise to unsafe levels, the detector will alert you.

How to Light a Pilot Light

Every water heater is a little different, so you should follow the instructions for your specific make and model of heater. In most cases, you can find details on a sticker affixed to the side of your water heater:

  • Turn the knob on the gas control valve to OFF and wait 10-minutes to allow the gas to clear the chamber area.
  • Turn the knob to PILOT on the gas control valve, and press the button. Pressing the button will allow a small amount of gas to travel to the pilot.
  • Press the small black (or red) igniting button repeatedly for 90 seconds. The igniting button will  generate a spark to light the pilot. (Some water heaters may need to be manually lit with a long lighter).
  • Once the status button begins to blink or turns on, the pilot light is lit. At this point, you can turn the knob to your desired temperature position. You should hear the burner ignite. This is normal.
  • If after 90 seconds, your pilot does not light, you’ll need to wait for 10-minutes before attempting again. If after several attempts you are unable to light the pilot, there may be something else going on. 

Do I Have a Bad Thermocouple?

Thermocouples are often called flame sensors in newer water heaters, but many heaters have a standing pilot light which uses a thermocouple. In this case, if the thermocouple is not properly working, the pilot light will not stay lit.

It’s possible that the thermocouple is dirty, bent or broken, and although, you may be able to reposition it or clean it, often the best choice is to simply have it replaced.

If you’re comfortable with DIY projects and working with gas appliances this task might be something you’re comfortable taking on. You can find out how here. But many homeowners choose to hire a professional plumber to do the job for them.

How Long Does it Take to Get Hot Water

Once you’ve got your water heater back up and running, it’s going to take awhile before you have hot water. How long depends on how large of a tank you have. In general, you should expect to wait between 30 to 40 minutes before your tank is fully heated.

Can I Turn Off My Pilot Light?

Generally speaking, there’s nothing wrong with turning off your water heater’s pilot light. Although, keep in mind, that you won’t have access to hot water once the water in the tank has cooled.

In fact, there are some scenarios where turning off your pilot light makes sense. For example, experts often recommend that you do so when going on vacation. Turning off your water heater’s pilot light will save money on your energy bill since the water heater won’t keep the water warm while you’re away.

Some homeowners prefer to turn their water heater to the pilot position instead of totally turning the pilot light off. Although, the heater will still use a small amount of gas to keep the pilot lit, it will be less of a hassle to turn the water heater back on when you return since you won’t need to relight the pilot.

When to Call a Professional Plumber

It’s never a bad idea to call a professional plumber out to take a look at your water heater. While they’re checking on your pilot light, they can also perform routine maintenance on your system. This is something that experts recommend you do at least once a year to avoid sediment build-up and corrosion, and proper maintenance will extend the service life of your water heater.

That being said, it’s typically not necessary to call a professional plumber out to light a pilot light. The solution to this problem is usually as simple as following the steps shown above.

However, you may want some help if you think the issue is coming from your water heater’s thermocouple. A professional plumber will be able to replace or repair your thermocouple fairly easily for you.

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