How To Relight A Gas Hot Water Pilot Light

pilot light gas hot water

When you are looking at relighting a pilot light on a gas hot water system it usually happens because of a change in gas pressure that caused the flame to go out. Usually, the main prompt to this instant gas hot water troubleshooting happens starts because you no longer have hot water. Knowing how to relight it is important so you can get the hot water running again but is also essential for safety reasons. You do not want gas accidentally being released in the home if you have a broken flame sensor.

How to light a pilot light

First of all, you should always check the instructions you have with your water heater. Different models and types of hot water systems will have slightly different instructions so it makes sense to follow the guide you have from the manufacturer. Many are very similar in the approach though so here is a look at what to do to light a pilot light on a gas hot water system.

  1. First, you need to find and turn off the gas at the shut-off valve. Usually, it is on the front of the heater, lower down. Wait for five minutes before you continue to step 2.
  2. Open the cover to the pilot light which you can find below the gas valve. On some heaters, you might have an open gap already where you can see the burner.
  3. With a headlamp or torch locate the burner, you should see two small tubes of gas near it.
  4. Twist the knob to pilot and hold it down and this gets the gas floe started to light the flame. In some cases, there may be another button for the pilot, often red in colour to hold and press.
  5. While holding the gas knob down use a flame to light the pilot, either a long match or lighter, or use the black or red ignite button if there is one.
  6. When it lights keep the gas button down for at least 60 seconds then slowly release it to make sure it stays lit.
  7. Turn the gas knob on and there should be a whooshing or whump sound as the main burner ignites. Put the cover back on if there was one.

If you are having repeated issues on lighting a gas hot water pilot light then that indicates more than just a natural change in the pressure of the gas. The more common reason for repeated pilot light problems is that the thermocouple is bent or dirty.

A closer look at the thermocouple

The thermocouple in newer models of hot water systems is called a flame sensor. It is made up of a rod and small copper wire that detects the flame and turns the gas off automatically if the flame has gone out. If it gets dirty, breaks or is bent the pilot light on a gas water heater will keep going out. If the problem is that it is bent and not near the burner anymore you can turn off the gas, move the thermocouple over and light the pilot once more and see if it works again. If that does not work you can have a professional service company handle it for you.

If the issue is that it is dirty then the valve and the main gas line should be turned off and it should be cleaned. Professional hot water plumbers will know how to do this without any risk of damage. They will unscrew the nuts that hold the thermocouple down as well as the two gas tubes. The burner can then slide out. They can vacuum the ports, clean the tips with the right items like steel wool or a microfiber cloth. If that does not get it working they can replace the thermocouple for you, it is not an expensive part to do so.


If you are having issues with your hot water system and when you light a pilot light on a gas hot water system it is not staying on, you should call in a local plumber near you to help you. Knowing how to relight it is fine for when the light going out is an uncommon occurrence, but repeated problems indicate something else is wrong and you should have it looked at by professionals so it does not turn into a bigger and costlier concern.