The Basic Steps to Light Your Rheem Water Heater

To light a Rheem gas water heater, you turn the control knob to the Pilot position, hold down the ignition button while holding a lit match or lighter to the pilot burner opening, and keep the button pressed for 30 to 60 seconds after the flame catches. Once the pilot stays lit on its own, you turn the knob to the On position and listen for the main burner to ignite within a few seconds.

The whole process takes about two minutes if the pilot lights on the first try. If it does not catch after 60 seconds of holding the button, release it, wait five minutes for gas to clear, and try again. Most Rheem units light reliably this way, but the exact location of the pilot opening and the shape of the control knob vary slightly by model year.

Key Takeaways

  • The control knob must be turned to Pilot before you press the ignition button, or gas will not flow to the pilot burner.
  • You need a lit match or lighter held directly at the pilot opening while pressing the ignition button—the spark alone will not light the gas.
  • Keep the ignition button pressed for 30 to 60 seconds after you see the flame, even though it feels like the pilot should light faster.
  • If the pilot does not light after one full minute, release the button, wait five minutes, and try again rather than holding it longer.
  • Once the pilot is lit and you turn the knob to On, the main burner should ignite within a few seconds; if it does not, turn off and wait before trying again.

Locating the Pilot Burner Opening on Your Rheem Unit

The pilot opening is a small hole or tube at the base of the burner assembly, usually inside the combustion chamber below the main burner. On most Rheem water heaters, you will see it when you open the access panel at the bottom front of the tank. The opening is typically brass-colored and about the size of a pencil tip.

If you cannot see the opening clearly, use a flashlight to look into the chamber. The pilot burner sits lower than the main burner, so you may need to angle your head or the light to spot it. Some Rheem models have a small metal tube that directs the pilot flame upward; the opening you light is at the end of that tube. Do not confuse the main burner opening (which is larger and sits higher) with the pilot opening.

Preparing the Control Knob and Ignition Button

The control knob on a Rheem water heater has three main positions: Off, Pilot, and On. Before you do anything else, make sure the knob is in the Off position and leave it there for at least five minutes. This allows any residual gas in the combustion chamber to clear out, which prevents a small explosion when you light the pilot.

After five minutes, turn the knob clockwise to the Pilot position. You will feel it click or stop at that setting. Do not turn it all the way to On yet. The ignition button is usually located just below or beside the control knob; it may be labeled "Ignition" or straightforward show a button symbol. Press it once to make sure it moves freely before you begin the lighting process.

Lighting the Pilot with a Match or Lighter

Hold a lit match or lighter flame near the pilot opening. A long-reach lighter or long fireplace matches work better than short matches because they keep your hand farther from the flame. Position the flame so it enters the pilot opening or sits just outside it—the gas will ignite when it meets the flame.

While holding the flame in place, press and hold the ignition button with your other hand. Keep both the flame and the button pressed simultaneously. You should see a small blue flame appear at the pilot opening within a few seconds. Once the flame is clearly visible and steady, continue holding the ignition button for another 30 to 60 seconds. This heats up a thermocouple (a heat-sensing device) that tells the gas valve to stay open and keep the pilot lit.

After 60 seconds, slowly release the ignition button while keeping the flame nearby for a few more seconds. If the pilot flame stays lit after you release the button, you have succeeded. If the flame goes out when ready, the thermocouple did not heat up enough—wait five minutes and try again.

Turning the Knob to On and Checking the Main Burner

Once the pilot is burning steadily on its own, turn the control knob from Pilot to On. This opens the gas valve to the main burner. Within a few seconds, you should hear a soft whoosh or click as the main burner ignites. The main flame will be much larger than the pilot flame and will burn with a blue color.

Look through the access panel to confirm the main burner is lit. If it does not ignite within 10 seconds, turn the knob back to Off, wait five minutes, and try the whole process again. Do not hold the knob in the On position and wait longer than 10 seconds—if the burner does not light by then, something is preventing ignition and holding the knob open only fills the chamber with unburned gas.

Common Mistakes That Prevent the Pilot from Lighting

The most frequent error is not holding the ignition button long enough. Many people release it as soon as they see the flame, but the thermocouple needs 30 to 60 seconds of heat to set up. If you release too early, the pilot will light while you hold the button but go out the moment you let go.

Another common mistake is forgetting to wait five minutes after turning the knob to Off. If you try to light the pilot when ready after shutting down the heater, unburned gas still fills the chamber and can prevent the pilot from catching. The five-minute wait is not optional—it is a safety step.

A third mistake is holding the flame too far from the pilot opening. The flame must be close enough to actually ignite the gas as it flows out. If you hold the match or lighter several inches away, the gas will not reach the flame. Position the flame so it is touching or nearly touching the opening.

When to Call a Professional Instead of Trying Again

If you have tried the lighting process three times and the pilot will not stay lit after you release the ignition button, the thermocouple is likely faulty and needs replacement. This is not a repair you should attempt yourself—a professional plumber or HVAC technician can replace it safely.

If you smell gas but cannot see a flame after pressing the ignition button for a full minute, turn the knob to Off when ready and do not try again. This suggests a gas leak or a problem with the burner itself. Open a window, leave the area, and call a licensed technician or your gas company's emergency line.

If the main burner will not ignite even though the pilot is burning steadily, the issue is likely with the main burner assembly or the gas line to it. Do not keep trying—turn off the heater and contact a professional.

Frequently Asked Questions

How long should I hold the ignition button before releasing it?

Hold it for 30 to 60 seconds after you see the pilot flame appear. The longer hold allows the thermocouple to heat up fully. If you release after only 10 or 15 seconds, the pilot will go out as soon as you let go.

What if I do not have a match or lighter?

You need an open flame to light the pilot—the spark from the ignition button alone will not work on a Rheem water heater. A long-reach lighter, fireplace matches, or a thin taper candle all work. Do not try to use the stove burner or anything that puts your hand too close to the pilot opening.

Can I light the pilot if the power is off?

Yes. The ignition button on most Rheem models is mechanical and does not require electricity. However, if your unit has an electronic ignition system (which some newer models do), you will need power to the heater for the ignition button to work. Check your manual or look for a power cord or electrical connection near the control knob.

Why does the pilot light but then go out after a few seconds?

You are releasing the ignition button too soon. The thermocouple needs 30 to 60 seconds of continuous heat to signal the gas valve to stay open. Try again and count to 60 before releasing the button.

Is it normal for the pilot flame to be small?

Yes. The pilot flame should be a small blue flame about the size of your pinky fingernail. If it is much larger or yellow-orange instead of blue, the pilot opening may be clogged or the gas mixture may be off—contact a technician to inspect it.