Water Pilot Light Keeps Going Out: 7 Reasons & How To Fix

Currently, a water heater is an essential part of your home, ensuring you always have access to hot water. However, when the water heater pilot light keeps going out, it can be a frustrating problem.

This article will delve into the workings of this component, the reasons why it might keep going out, and provide tips to prevent this issue from recurring in the future.

What is The Pilot Light, and How Does it Work?

The pilot light is a small gas flame that stays lit continuously. It helps ignite the gas burner on your water heater. In other words, without it, you cannot take hot showers.

The pilot light in a water heater is a small gas flame

The Reason Your Water Pilot Light Keeps Going Out & Solution

Various issues could cause your water heater pilot light to keep extinguishing. Here are the most common reasons:

A Dirty Pilot Tube

Your water heater is a reliable buddy. Day in and day out, it provides you with the hot water you need for showers, dishes, and more.

But sometimes, stuff gets in the way. Dust particles, debris, and the occasional adventurous insect might find their way into the pilot tube and cause a blockage. So, the gas can’t get through to the pilot light as smoothly as it should, leading to the flame starting to falter. Thus, without a steady gas supply, your pilot light can’t keep up, and it goes out.

Moreover, without it, your water heater can’t do its job. As a result, your hot water turns cold, affecting your showers, your dishwashing, and more.


You should keep the pilot tube clean to ensure that gas can flow freely, keeping your pilot light, and in turn, your water heater, working efficiently. When you clean, and you put it back, if the flame is blue and steady, it’s done. It’s a simple task, but it makes all the difference in your daily comfort at home.

An Unclean Thermocouple

The thermocouple is an important part of your water heater’s safety system. Its role is to follow the pilot light’s flame. If the flame is burning as it should, the thermocouple signals that it’s safe to continue supplying gas.

However, just like anything else, the thermocouple can become dirty over time. This layer of grime can interfere with its ability to correctly sense the pilot light’s flame. For example, if the pilot light is on and burning, a dirty thermocouple might not be able to detect it.


Therefore, it’s essential to keep the thermocouple clean. A well-maintained thermocouple can accurately detect the pilot light, enabling your water heater to operate smoothly.

First, you should ensure safety by turning off the gas valve. After turning it off, you allow the thermocouple to cool down. Now, it’s time to clean. Take a piece of new sandpaper and gently scrub away the dirt and grime from the thermocouple.

A Kinked Thermocouple

The thermocouple, in its role as the sentry of the water heater, needs to be in the right position to work effectively. Normally, it should be close enough to the pilot light to accurately sense its flame.

However, if the thermocouple gets kinked or twisted out of its proper position, so, it may end up too far from the flame to detect it accurately.

When it can’t sense the flame, the thermocouple assumes that the pilot light is out. Thus, it will shut off the gas supply to the water heater to be safe.


Thus, it’s essential to ensure your thermocouple is not kinked and is correctly positioned to sense the pilot light’s flame.

First, you need to turn off the gas supply and switch off your heater to be safe. When you’re done, let the thermocouple a little bit of time to cool down.

After it’s cool, now, you should manually adjust the thermocouple, bringing it back to its correct position.

In detail, you ensure the thermocouple is close enough to the pilot light. It should be near enough to either slightly touch or encircle the blue part of the flame. This simple adjustment can help maintain a steady supply of hot water in your home.

A Damaged Thermocouple

Alright, you’ve cleaned the thermocouple and made sure it’s not twisted out of position. But your water heater’s pilot light continues to go out. It’s frustrating, isn’t it? Thus, maybe the issue comes from the broken thermocouple.

Before you give up on your thermocouple, do a diagnostic test with a multimeter. If the voltage supplied by your thermocouple is way less than 20MV, then the device is surely broken and needs to be replaced. If its output voltage is significantly less than 20 MV, the component is undoubtedly damaged and needs to be replaced.


Let’s say you’ve tested your thermocouple with a multimeter, and the reading is close to, but not exactly 20MV. In this situation, you can try nudging the thermocouple closer to the pilot light.

However, if the multimeter reading is significantly lower than 20MV. In such a case, you have no choice but to replace the broken component.

Using the multimeter to test your thermocouple

Flex Tube Problems

The flex tube in your water heater serves a critical role by transporting gas from the control valve to both the pilot light and the thermocouple.

However, if the flex tube is bent, kinked, or damaged in any way, it can result in an inconsistent supply of gas.


Fortunately, problems with the flex tube are not as frequent as issues with the thermocouple. Therefore, it is important to prioritize checking the condition of the thermocouple before focusing on the flex tube.

To solve this problem, straighten any bends or kinks present in the flex tube. Additionally, it is advisable to carefully inspect the tube for any visible signs of damage that could potentially lead to gas leaks. Gas leaks can result in a reduced supply of gas reaching the burner.

A Faulty Main Control Valve

The issue related to the main control valve is exceptionally rare, but it is important to check other components such as the pilot tube, thermocouple, and flex tube before checking this part.

However, it should not completely look like a potential cause if your pilot light keeps going out. This crucial component helps adjust both the gas and water pressure within the water heater.

The process begins with the main control valve unit supplying a small amount of gas to ignite the pilot light. Once the gas is successfully ignited, it proceeds to fully open the main valve, ensuring a steady and continuous gas supply.

If the Main Control Valve Unit is faulty, it may unexpectedly close the gas valve, leading to a disrupted gas supply and resulting in a weak flame.

Several signs that may indicate a problem with the Main Control Valve:

  • The pilot button fails to pop up after being pressed.
  • The control knob shows malfunctioning behavior.
  • The water temperature exceeds the specified range, becoming excessively hot.

By identifying these indicators, you can recognize a potential issue with the Main Control Valve Unit, which plays a vital role in the overall functionality of your water heater.

The main control valve issues can cause the pilot light keeps going out


When it comes to a faulty main control valve, there are no viable alternatives for repair. Despite some technicians claiming to have the ability to fix this component, manufacturers strongly discourage such attempts.

The recommended action is to replace the faulty main control valve instead. By doing so, you can prevent issues associated with repairs to the other parts of your water heater from potential damage.

Replacing the malfunctioning main control valve is the most advisable approach, ensuring the optimal performance and longevity of your water heater while avoiding potential complications.

Poor Electrical Wiring

Additionally, the issue occurs in electric water heaters. One of the indications of a faulty electrical system is the sudden shutdown of your water heater.


To address this problem, it is crucial to promptly turn off your water heater and seek assistance from a qualified technician. It is strongly advised not to attempt any intervention or modification of the wiring system on your own.

Tips to Prevent Future Issues

First, regular maintenance is key to preventing issues. In detail, you should often clean the pilot tube and thermocouple, and check for kinks in the flex tube. Moreover, you also should ensure the main control valve is working properly. If your heater uses an electric ignition, ensure the wiring is in good condition.


When your water heater’s pilot light refuses to stay lit, it’s not just a minor annoyance. It’s often a sign of potential issues demanding your attention. By being familiar with these common problems and staying on top of routine maintenance, you’re taking crucial steps to keep your hot water flowing consistently. After all, a reliable supply of hot water is essential for comfort and convenience in our daily lives.


Why does my water heater pilot light keep going out?

There could be several reasons, including a dirty or kinked thermocouple, a clogged pilot tube, flex tube issues, or a faulty main control valve.

How can you determine if there is a problem with a thermocouple?

You can diagnose a potential issue by using a regular voltmeter set to the Ohm’s/Continuity function. By testing the positive and negative leads and measuring the resistance, you can determine whether the circuit in the thermocouple probe is open or closed.

How often should I perform maintenance on my water heater?

You should perform maintenance on your water heater at least once a year. However, components like the pilot light and thermocouple should be checked more frequently, perhaps once a month, to ensure they’re working properly.

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