Water Heater Pilot Light Keeps Going Out? Causes and Safe Fixes

You relight the pilot, get a hot shower, and two days later the water is cold again. A pilot that keeps going out is one of the most common gas water heater calls we get around Carmel, Westfield and North Indianapolis. The cause is usually a small, fixable part, but it is also your water heater telling you something needs attention.

Here is what is going on inside that burner compartment, how to relight it safely, and when to hand it off to a plumber.

How the pilot and burner work together

On a standard gas tank, a small pilot flame burns all the time. When the water cools below your thermostat setting, the gas valve opens and the pilot lights the main burner. Three parts keep that system running:

• Thermocouple or flame sensor: a small metal probe that sits in the pilot flame and tells the gas valve a flame is present.

• Gas control valve: the box with the knob on the front. It controls gas to the pilot and burner.

• Pilot assembly: the tube and tiny orifice that feed and shape the pilot flame.

If any one of these gets dirty, worn or knocked out of position, the valve shuts the gas off as a safety measure and the pilot goes dark.

Common reasons the pilot won't stay lit

A worn or dirty thermocouple

This is the usual suspect. Over time the tip gets coated or weak and stops sending a strong enough signal, so the valve closes even though the flame looked fine. We test its output with a meter before replacing it, so you are not paying for a part you did not need.

A clogged pilot orifice

Dust, lint and rust flakes can partly block the pilot opening. The flame turns small, yellow or lazy and does not wrap the thermocouple well. Basements and utility rooms with laundry nearby are prone to this, since dryer lint gets pulled toward the burner air intake.

Drafts and venting problems

A water heater near a garage door, open window or return air vent can have its pilot blown out on windy days. A vent pipe that is loose, poorly sloped or partly blocked can also pull the flame sideways or push exhaust back down. Our Indiana winters make this worse, since cold outside air and a tight house can change how the vent drafts.

A failing gas control valve

Less common, but it happens, especially on older units. If the thermocouple tests good and the pilot still drops out, the valve itself may not be holding open. Gas valve work should always be done by a licensed plumber.

Moisture in the burner area

Water dripping from a fitting above, condensation, or a tank that has started to leak can rust the burner and splash the pilot. If the moisture is coming from the tank itself, that points toward replacement rather than repair.

How to relight the pilot safely

If you smell gas, stop. Do not light anything or flip switches. Leave the house and call your gas utility or 911 from outside.

If there is no gas smell, follow the instructions on the label on your tank. On most standing-pilot models the steps look like this:

1. Turn the control knob to OFF and wait at least 5 to 10 minutes for any gas to clear.

2. Turn the knob to PILOT and press it down.

3. While holding it, press the igniter button (or use a long lighter) until the pilot lights.

4. Keep holding the knob for about 30 to 60 seconds so the thermocouple heats up, then release.

5. Turn the knob to ON and listen for the main burner to light.

If the pilot will not stay lit after a couple of tries, stop there. Repeated relighting will not fix the cause, and it is time for someone to test the parts.

Repair or replace?

Most pilot problems are repairs: a thermocouple, a cleaned pilot assembly or a corrected vent. We fix those whenever the heater is otherwise in good shape. Replacement starts to make more sense when:

• The tank is showing rust or moisture at the bottom.

• The heater is well past 10 years old and has had several service calls lately.

• The gas valve has failed on an older unit.

If a new heater is the better value, we will walk you through why. We install Bradford White tanks and Navien tankless units, and same-day replacement is often available.

Keep the pilot happy

• Keep the area around the water heater clear, dry and free of lint and stored chemicals.

• Do not block the air openings at the bottom of the tank.

• Check that the vent pipe on top is snug and not dented.

• Flush the tank periodically, since hard Hamilton County water builds sediment that makes the burner work harder.

When to call us

Call if the pilot goes out more than once, if the flame looks yellow or sooty, or if you see water around the base. A tech will test the thermocouple, check the draft and gas pressure, clean the pilot and confirm safe combustion before leaving. You can read more about our water heater repair and replacement service, and for a gas smell or active leak, our emergency plumber page has what to do first.

FAQ

Why does my pilot light go out overnight or on windy days?

Wind and drafts are a big clue. A draft near the heater or a vent that is not drawing well can snuff the pilot, especially in cold weather. A weak thermocouple can also fail more easily when conditions are not perfect.

Is it dangerous if my pilot keeps going out?

The safety system is doing its job by shutting off the gas, so a pilot going out is not dangerous by itself. The concern is the cause, such as poor venting, which can affect carbon monoxide safety. Make sure you have working CO alarms and have it checked.

Can I replace a thermocouple myself?

Some handy homeowners do, but it involves gas connections and the part must be the right one for your valve. If you are not comfortable working on gas, leave it to a licensed plumber who can also test why it failed.

Do newer water heaters still have a pilot light?

Many newer gas tanks use electronic ignition or a sealed combustion design that is less prone to drafts. Tankless units like Navien use electronic ignition with no standing pilot at all.

How much will the repair cost?

It depends on which part is at fault and the model you have. Your plumber diagnoses it on site and gives you options and a price before any work starts.

Pilot light giving you trouble? Call or text (317) 731-3028, or request service online.