How To Light A Pilot Light On A Water Heater (Detailed DIY Guide)

Your water heater provides you with a reliable water supply for cleaning and showering. There's a wide variety of water heaters on the market, but many use gas as the primary power source.

For a gas water heater to work, it needs a pilot light to ignite the gas and heat your water. In this guide, we'll help explain how to light a pilot light and what you can do to keep your water heater running as it should.

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How To Light A Pilot Light On A Water Heater (Step By Step Guide)

Lighting your pilot light is a reasonably straightforward task, and once you've done it a few times, you won't even need to think about it. Remember that safety always comes first, and even though it's simple, you don't want to get complacent. You are handling gas and electronics, so if anything starts to go wrong, don't be afraid to call a professional for help.

There are two types of gas water heater pilot lights: sealed combustion heaters and unsealed combustion heaters.

The process is similar for each, with one key difference. Sealed combustion heaters have built-in sources of ignition, which are usually activated by a switch. Unsealed combustion heaters often need an external ignition source for the pilot light, usually a match or lighter. Here’s a step-by-step guide for each:

Lighting A Sealed Combustion Pilot

1
Find Your Controls
Everything you need to light a sealed combustion pilot will be found on the outside of the module. There will be a small glass access panel that allows you to see if the flame is lit, an ignition switch, and a gas control knob. Make sure you know where everything is before you start.
2
Start The Gas Flow
Turn the gas knob to the pilot position and then push it in. Keep it pushed in to allow the gas to flow.
3
Ignite The Flame
Press the electronic ignition switch until you hear it click. You may need to press this multiple times and hold it for a few seconds before it ignites the flame.
4
Check The Flame
Look through the glass panel and make sure the blue flame is showing. Keep holding the gas control knob in for 30-45 seconds to make sure the pilot light remains lit. After 45 seconds, let go of the control and make sure the pilot light remains lit.
5
Adjust The Gas Flow
Adjust the control knob to the on position. Some water heaters will have a variety of settings for gas flow which will provide more heat. Adjust the control knob to the most appropriate setting and let your water heater run. Your pilot light should now hopefully remain lit, and your burners will kick in to heat your water.

Lighting An Unsealed Combustion Pilot

1
Select Your Ignition Source
You'll need to light the pilot light yourself with these water heaters, so make sure you have matches or a lighter handy.
2
Open The Burner Compartment
Lift off the covering panels to the burner compartment so you can access the pilot light. The covers should move away easily enough.
3
Adjust The Gas
Turn your gas supply control knob, so it's lined up with the supply button. This will allow you to push it in easily when it's time to let the gas flow.
4
Light The Ignition Source
Light your match or lighter and put them into the burner compartment. This will help remove any excess gas lingering in the compartment, and it will quickly burn off.
5
Activate The Gas
Push the gas supply knob button in to activate the supply. This should allow your pilot flame to catch. Continue to hold the supply button in for 30-45 seconds until you’re sure the pilot flame is on.
6
Turn The Gas On
Release the gas control knob and make sure your pilot light stays on. Turn the control to the on position, and your water heater should start to activate. Your burners will begin to heat the water and continue to provide you with hot water as needed.

How Does A Water Heater Pilot Light Work?

Your pilot light is typically found just inside your water heater near the front of the device, so it's easily accessible. Gas-powered water heaters are reliant on pilot lights to light the gas, and without it, no heat will be produced.

The pilot light operates like a match on an old gas stove. The gas will run when you switch it on, but without a spark or ignition, no heat can be produced. Your pilot light should run the whole time your water heater is operating and give a continuous ignition source to the gas or propane supply.

How To Tell If A Water Heater Pilot Light Is Out?

Your pilot light needs to run continuously, so it's important you recognize the signs that it's gone out:

No Hot Water
The most obvious sign that your pilot light is out is that there's no hot water. This is a sign that the heating mechanism isn't operating as it should, and the most common reason for this is an issue with the pilot light. There are a few other reasons you won't have access to hot water, but you should always check the pilot light first.
Blinking Light On Gas Control Valve
Most modern water heaters have control panels with indicators that blink if there's an issue. If you notice some of the lights have started flashing, it could mean your pilot light has gone out. Your user manual should have a full breakdown of what the flashing lights mean and can even help you determine why the pilot light has gone out. It’s often linked to your thermocouple, and your control panel will be able to tell you if it’s broken or blocked without having to open up the whole machine. It’s worth investing the time to understand what the indicators on your water heater mean.
No Visible Flame
Your water heater will have a clear observation panel on the front or side which allows you to see the pilot light. If you can’t see the flame, it means it's gone out, and your heater won't operate properly. This can happen because the flame has been blown out because of a draft or because there's a change in gas pressure. It can also mean there's not enough combustible air around the water heater, and you might need professional help in resolving it.

How To Fix Faulty Water Heater Pilot Light

Your water heater pilot light can go off for a wide range of reasons, and you'll need to carry out some troubleshooting. Before you get started, you’ll need the following equipment:

A screwdriver
An adjustable wrench
Dish soap and water
Matches/Ignition Source
A new thermocouple

Once you've gathered your tools, you should follow these steps to understand and resolve the problem. First, make sure you've turned off the power and gas supply before replacing your thermocouple, or it could be dangerous.

1. Try Relighting The Pilot Light

If you’ve noticed the light has gone out, you should start by relighting it. Follow the steps detailed above in this article and see if that does the trick. Repeat this 3 or 4 times, leaving a minute or so in between attempts.

2. Check The Wiring

If you have an electronic pilot light ignition, you need to ensure enough power is reaching it to light the flame. Open up the access panel and check for any loose wiring or disconnected ends that might be disrupting the power supply. You may need to resolder some of these so they stick in place.

3. Check The Thermocouple

Your thermocouple controls the flow of gas into your water heater by detecting when your pilot flame is lit.

This is almost always the issue, and your water heater probably needs a new thermocouple to be installed.

Start by opening up the access panel and seeing if the thermocouple is loose. You should be able to tighten this with an adjustable wrench.

4. Replace The Thermocouple

If the problem isn't resolved, you may need to replace the thermocouple. To do this, you'll have to follow these steps:

Remove the burner access panel unscrew the nuts connected to the thermocouple, gas, and pilot lines.
Pull out the burner assembly of the water heater and remove the old thermocouple. You may need to undo some screws before you pull the thermocouple out.
Get a replacement thermocouple that matches the shape and size of your old one. It's often useful to take your damaged one to a hardware store so you can match it exactly.
Install the new thermocouple where the old one was and tighten any screws around it. Then, slide the burner assembly back into place.
Reattach the lines into the control valve and reattach the gas line. Make sure you thread the nuts into place and then tighten using the wrenches, so they're all snugly connected.
Test the gas line or any leaks by applying dish soap and water around the connections. Turn the gas supply on and relight the pilot light. If you notice any bubbles in the soapy water, it means there's a leak, and you need to consult a professional. Gas can be deadly, and it's imperative that you carry out this test once you've finished work.

Remember, some water heaters have a closed access panel and are difficult to access. If this is the case, you’re better off calling a professional because it can be hazardous to do it yourself.

5. Consult A Professional

If your water heater pilot light still isn't working and you can't get hot water, you'll need to consult a professional. There are a few other causes, but most of them are too technical to attempt on your own.

Conclusion

Your water heater plays a vital role in your day-to-day life, but it's useless without the pilot light. Knowing how to light your pilot light will help keep the hot water flowing, and hopefully this guide has helped explain how to do this yourself. It's a simple enough process but does involve gas, so don't be afraid to involve a professional if you feel like you're out of your depth.

How To Light A Pilot Light On A Water Heater