Water Heater Pilot Light Won’t Stay Lit: What to Do


There is nothing as frustrating as rushing to take a hot bath only for your water shower head to give you cold water. This could be because of several reasons, but if it because of your water heater, it can be more frustrating. If it is the case, you may check for signs like if the water heater pilot light won’t stay lit to begin troubleshooting.

If the gas water heater burner won’t stay lit, you may have a bigger problem than taking a cold bath. However, if you are a well-versed DIYer, you can troubleshoot it and check the mishaps. If the gas water heater pilot won’t stay lit after several trials, you may call a professional technician to help you out.

Reasons Why Your Water Heater Keeps Turning Off

Like most tools and equipment at home, there are many reasons why your water heater keeps turning off. It is rather unfortunate that the reasons can be several, some known but others unknown to you. In either case, understanding the causes will help you to prevent future heating outages and save money, eventually.

The potential reasons why you water heater keeps turning off or the water heater pilot light won’t stay lit include:

Main Control Valve

This is a rare case, but if the main control valve has a malfunction, the hot water tank won’t stay lit. However, this valve seldom goes out, and you should, therefore, explore the other possibilities as explained below. You should not rule it out altogether, and if it is bad, you may need to replace it with several tools from your tool set.

Obstructed Thermocouple

Most of the old water heaters use a thermocouple as the main operating organ. If the water heater keeps turning off, the thermocouple may be obstructed from reading the electrical current that indicates if the pilot light is on or off. The thermocouple is designed to turn off gas supply whenever it detects an unlit pilot for safety precautions.

If the thermocouple is not functioning as it would, you will need to troubleshoot it and identify what could be obstructing it. Some of the obstruction may be from dirt which can be cleaned easily with sandpaper. When doing so, however, you should ensure that the gas is off and that the thermocouple is cool for you to touch.

Damaged Thermocouple

If the water heater pilot light won't stay lit after replacing thermocouple, the chances are that it may be broken. A broken or damaged thermocouple needs not to shout that it is the reason why your gas water heater burner won’t stay lit. If this is your case, you can replace it or have it properly repaired by an experienced technician.

Curved Thermoc​​​​ouple

Apart from being obstructed or damaged, a curved thermocouple may cease being functional. This is especially so if it is bent too far away from the pilot, limiting it from registering the latter’s heat.

If the gas water heater pilot light won’t stay lit because of a bent thermocouple, you can rectify that yourself. You only need to bend it back to the original position but make sure it is close to the flame of the pilot enough to heat it. To check the results, a healthy pilot light will show or appear blue.

Flex Tube Issues

If the hot water heater won’t stay lit after trying all troubleshooting approaches, you may check for flex tube issues too. The flex tubing is the tube that connects to the gas controller and ensures a steady gas stream. If it is kinked in places, it will prevent a smooth operation or flow of gas.

If this happens to be the problem, unkinking it will help to resolve the issue if the hot water heater won’t stay lit. You may keep on checking and unkinking it occasionally if it is the sole problem often. If the unkinking does not help, installing a new tubing would be preferable.

Flex tube issues are less common and rarely lead to a gas water heater pilot light that won’t stay lit. It is less frequent compared to thermocouple issues but should not be ruled out when troubleshooting issues with your gas water heater. If the thermocouple check turns out negative, you should check the flex tubing too.


A gas heater is one of the oldest water heating ways. It is a sustaining method but can be frustrating if the water heater pilot light won’t stay lit, and you cannot identify the problem. As expounded, the reasons can be varied, and identifying the main ones may be a tough process, but one that will pay off when you can eventually troubleshoot and repair it.

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