Water heaters are one of the essentials in any household. But, it’s a nuisance when it isn’t working correctly. In such cases, a common cause is the pilot light going off at random times.

But, why does the pilot light of your water heater not stay lit?

If the pilot light of your unit keeps shutting off, the most obvious thing to look up to is the thermocouple. The common area for this problem can be on the water heater used for residential purposes. However, it may not be the only reason.

So, here are eight potential reasons why your water heater pilot light won’t stay lit:

Table of Contents

8 Reasons Why Your Water Heater Pilot Light Won’t Stay Lit

1. Obstructed Thermocouple

Most water heaters need a thermocouple. You can quickly know if the pilot light is on or off with the help of an electrical current, powered by the pilot’s heat.
When the thermocouple becomes dirty, the electric current passing through the pilot may get obstructed. This situation may lead to a gas outage and cause the pilot light to turn off. In case the thermocouple detects an unlit pilot, it automatically shuts down the gas for safety precaution.

To fix this problem, locate the thermocouple and scrub it with sandpaper. Don’t forget to turn the gas off and check if the thermocouple is cool enough to touch before you start cleaning it.

2. Curved Thermocouple

Besides the dirt and grime, a thermocouple can also bend to the point where it can no longer function. If the thermocouple curves way too far from the pilot, it can’t register the heat.

To fix this, bend the thermocouple to its original position. Make sure the thermocouple slightly touches the flame or is close enough to the fire of the pilot. It is better to look at the light and ensure it is wrapped around the sensor.

3. Damaged Thermocouple

If there are no signs of clog or bending of the thermocouple, then most probably, the device is broken. In this case, you should repair the thermocouple, or replace it. In either case, make sure you turn off the gas for safety. To restore the thermocouple, simply detach the furnace cover and unscrew the device.

To check the condition of the thermocouple, test its incoming voltage with a multimeter. If the reading is below 20 MV, it indicates that the thermocouple requires maintenance.

4. Dirty Pilot Tube

If the thermocouple of your water heater has no issue, it could be the filthy pilot tube. Sometimes, the dirt can build up and block the flow of gas in the pilot tube.

Luckily, it is pretty easy to fix this issue! All you have to do is turn off the gas and let the pilot cool down. Once the pilot cools down, simply take a needle and clean the tube. Make sure to remove all the large particles that might block the path.

5. Flex Tube Issues

Another possible reason for the pilot of your water heater to not light up could be due to the issues with flex tubing. This specific tubing connects directly to the gas controller and also ensures a steady stream of gas. However, at times, the pipe twists around, preventing the proper operation of the system.

In this case, untwining the tubing will occasionally solve the problem. If it does not solve the issue, you need to replace the tubing of the system. However, flex tube issues are less frequent compared to thermocouple issues.

6. Main Control Valve

On rare occasions, a problem with the main control valve can also cause the pilot light to shut off. But, you should check other options before checking the issues with the main valve.

If there is an issue with the main control valve, you need to replace the entire valve to fix the problem. Remember, the valve is a crucial part of the heater and the impetuous act can lead to a water heater explosion.

7. Defect in Electrical System

Improper wiring can also affect the pilot light of your water heater. This issue is more common in electric water heater compared to gas-powered units. If your water heating unit has improper wiring, it can face several electrical problems.

In such cases, your unit will no longer be able to heat the water. If your water heaters have an electrical defect, the breaker shutdown will automatically shut down the main fuse or breaker. So, consult a specialist to inspect the electric wiring.

8. Defective Burner

Make sure to check the defective burner. If your water heater has a faulty burner, it will not ignite the unit, causing the pilot light to turn off.

If you suspect that the burner of your water heater is damaged, the only way to solve this is by replacing the entire burner.

How to Reignite the Pilot Light

If you’re facing problems with the pilot light of your water heater, fix the issue as soon as possible. Well, here are some methods to reignite the pilot light of your water heater:

DIY Method

If you’re willing to reignite the pilot light by yourself, you should always be extra cautious.

First, switch the thermostat to heat mode and get it up to 80 degrees. Now, find the pilot valve on the furnace, locate the on/off knob, and turn the knob ‘off.’

The pilot light is next to the gas burner tube. Ignite the flame and switch the knob to ‘pilot’ and hold it for about 35 seconds. Once the pilot catches fire, turn on the knob.
If the strategy does not work, repeat the entire process, and wait a minute instead of 35 seconds. So, the thermocouple gets hot enough to signal the pilot light to turn on.

Claim Your Warranty

Generally, most water heaters in the market have at least a year-long warranty. So, get your heater checked with an authorized distributor from whom you purchased the unit.

Hire an Expert

If your water heating system has exceeded the warranty period, hire a technician to solve the issue.

You may feel like you can fix the heater on your own, but it’s always best to take the safe route since it involves dealing with gas and electricity.

If you try to repair it by yourself, it may cause further damage and cost.

Final Thoughts

If the pilot light has issues, multiple reasons can lie behind it. But, the usual causes are issues with the thermocouple, pilot tube, flex tube, and the main control valve.

We hope this article can at least be of little help to you.

(Last Updated on June 15, 2020 by Sadrish Dabadi)

Nina Howell is a Rewenable Energy researcher and consultant based out of Houston, Texas Area. She earned her Master's Degree in Energy and Earth Resources from Austin Jackson School of Geosciences in 2010, and a Bachelor's Degree in Environmental Science from State University of New York College of Environmental Science and Forestry in 2008. Nina has been working in the energy sector since 2011. She worked as an Energy Supply Analyst from 2011 to 2017 in Bounce Energy and then as a Research and Energy Consultant at GE Renewable Energy from March 2017 to February 2020 . Nina is a mom of 2 beautiful children who are joy to her life. She strongly believes in eco-friendly living and is vocal about renewable energy, environmental issues, water crisis, and sustainable living.