If you are reading this, it is quite likely that you have experienced the inconvenient and frustrating issue of finding that your hot water is cold. If you have a gas water heater, chances are, the issue is a case of your pilot light going out. The good news is, that this is usually caused by a simple issue and may be resolved easily. Many homeowners face this issue from time to time. The true test comes with determining WHY that pilot light has gone out. In this brief guide, we will review the cause of a blown-out pilot light on a water heater. Continue reading to learn more.

What is the Pilot Light?

The pilot light is the ultimate source of heat for your hot water heater. It burns petroleum-based gas to create heat. If you look underneath the structure, it is a small flame that is usually blue in color. If this goes out, the water within the tank will not heat, leaving you with only cold water throughout your household.


Issue #1: Blown-Out Pilot Light

One of the easiest of all issues when it comes to the pilot light going out is that it simply got blown out. This can happen as a result of activity occurring near the water heater, drafts, and even moisture in the air. It may also occur if one of the ducts on the furnace is leaking air. Furthermore, it could occur if the flame is turned down too low.

Issue #2: Dirty Pilot Tube

The pilot tube is that which supplies the gas to the light area for the purpose and intent of combustion. As time progresses, dust, dirt, and debris may accumulate on the inside of the tube. You just have to take a thin needle and clean the interior sides of the tube. It may take some time, but once you are confident that the debris has been eliminated from the tube, you may then attempt to relight the pilot.

Issue #3: Clogged Thermocouple

There is a component in your hot water heater that is responsible for clothing the valve that puts out the gas. This is done with the part senses that the pilot light is no longer on. It is the thermocouple. The pilot light results in the development of an electrical current that controls this part. It helps to ensure that gas does not leak. If this component becomes clogged with debris, it will automatically shut down the gas supply. In turn, this will turn off the pilot light. To clean, turn off the main gas supply and let the part completely cool. Then, take a little sandpaper and scrub off the debris.

Issue #4: Bent Thermocouple

If the pilot light is off, check the thermocouple to see if there are any kinks. If you do see that it is bent, turn off the gas supply and the hot water heater. Then, allow the component to completely cool. Then, you can bend it back into place. Make sure it is in close proximity to the pilot light. It should be in a position that allows it to touch the flame once the pilot is lit. If this is bent, it will shut off the gas supply to the unit. When this happens, the pilot will automatically shut off.

Issue #5: Faulty Thermocouple

If you have cleaned and straightened the thermocouple and the pilot light still is not working, it is likely that the part is faulty and needs to be replaced. You will need to check the part with a multimeter diagnostic test. If you see that it is putting out less than 20MV, the part is in need of replacement. You should consult a professional plumber for this test. That way, if the part needs to be replaced, it can be easily done without putting yourself at risk.

Issue #6: Flex Tube Issues

There is a long tube that directly connects the controller of the gas to the burner where the pilot light is located. If this becomes clogged up or damaged in any way, the gas supply will immediately stop and the pilot light will not light. If you have noticed a flickering pilot light or it continuously goes out, it is likely that this is damaged or dirty. In either instance, it is just best to replace the flex tube. Even if you clean out the original flex tube, there could still be very small holes or cracks that could result in gas leaks. This is very dangerous. It is an inexpensive part and can easily be replaced.

Issue #7: The Main Control Valve

If you have checked all of the issues previously mentioned in this guide, it could be that you have a problem with the main control valve. It must be stated that this is a rare event, but it is not impossible. This part regulates the gas and the water pressure of the hot water heater. It provides a little gas to the pilot light. Then, if the pilot light is lit, it will open the mail valve so that the gas is steadily supplied to the product. If faulty, this will close the gas valve and shut off the supply of gas – which will create issues with the flame of the pilot light.

Signs that your main control valve is bad include a pilot button that will not pop after reset, a control knob that does not work properly, and hot water that is way hotter than it is supposed to be or normally is. If you find that this is the reason that your pilot light is going out, the entire valve will need to be replaced. You should avoid fixing certain components. If left in bad shape, it could start damaging other parts of the water heater.

Issue #8: Electrical Issues

If the pilot light shuts down, check to see if electricity is going to the hot water heater. If the electricity has shut down, too, it could be a case of electrical problems. If you find that this is the case, turn off the water heater completely and immediately call a professional. You should never attempt to manipulate or fix the wiring yourself. This could pose a significant risk to you and your home. Immediate professional assistance is required.


In most instances, a blown-out or improperly working pilot light on a hot water heater is an easy fix. In fact, most of the time, it will just be a case of an accidental blow-out. Perhaps a draft or nearby movement blew out a low-burning pilot. It could be that a little moisture found its way to the flame and put it out. Then, it could be one of the other issues that were mentioned in this guide – the worst being the main control valve and electrical issues. Regardless, we can help you!

Reynold’s Plumbing has been helping customers just like you for the past several decades. In addition to plumbing, we also specialize in HVAC. It does not matter if you have an issue at home, at work, or in a restaurant, we can assist you. If you live within the area of Richmond, Indiana, we are just a phone call away! Regardless of what is occurring at your home, we are your one-stop source of assistance!