How to Light a Rheem Gas Water Heater Pilot Light Safely

It’s 6:30 AM, the water’s ice cold, and you’re staring at the base of your Rheem gas water heater wondering if you’re about to blow up your garage. Take a breath. Relighting a pilot light is a routine job most homeowners can handle in under fifteen minutes, but only if you follow the right sequence and respect the safety rules. This guide walks you through the entire process for Rheem’s common valve designs, including the older manual knobs and the newer electronic ignition models with a small status light.

You’ll learn the exact knob positions, the waiting periods, and the troubleshooting steps when the pilot won’t stay lit. I’ll also cover the difference between a healthy blue flame and a lazy yellow one, and I’ll tell you plainly when you should stop fiddling and call a plumber. No guesswork, no vague advice—just the procedure I’d use on my own tank.

Before you touch anything, know this: the process differs slightly depending on your Rheem model. Older units use a standing pilot with a simple thermocouple. Newer ones use an electronic ignition module that requires a different relight sequence. I’ll cover both so you can identify which one you have and act accordingly.

Before You Start: Safety Warnings for Gas Appliances

Natural gas and propane are safe when contained, but a pilot light is literally an open flame inside a metal box. The first rule: if you smell gas, stop. The smell of rotten eggs is the odorant added to natural gas so you can detect leaks. If you smell it strongly, do not light anything, do not flip any electrical switches, and do not use your phone inside the house. Leave the door open on your way out, get everyone outside, and call your gas utility from a neighbor’s phone. Wait for a professional to clear the area.

If the smell is faint or you’re not sure, open a window near the water heater and wait five minutes before proceeding. The gas needs time to dissipate. A small lingering odor after a pilot outage is normal—the gas line has a few cubic feet of gas in it that needs to clear. But a persistent or strong smell means a leak, and that’s not a DIY situation.

One more thing: keep flammable materials away from the water heater. Cardboard boxes, paint cans, cleaning solvents—move them at least three feet away before you start. The pilot flame is small, but the burner underneath can kick on while you’re working, and you don’t want a face full of flame.

Tools You’ll Need to Relight the Pilot

You don’t need a toolbox full of gear. Here’s the short list:

• A long-stemmed lighter or a grill lighter with a flexible neck. Matches work but are harder to control and can burn your fingers.
• A flashlight. The burner compartment is dark, and you need to see the pilot tube clearly.
• A flathead screwdriver. Some Rheem models have a small access panel held by one or two screws.
• Your owner’s manual, if you have it. The exact procedure for your model is printed on the gas valve label or the inside of the access panel. If you don’t have the manual, the label on the valve itself often has a diagram.

That’s it. No special tools, no expensive gadgets. If you have a newer electronic ignition model, you might also need a small mirror to see the status light, but a flashlight usually does the job.

Before you open anything, turn off the water heater’s gas supply valve? No, wait. You don’t need to shut off the main gas line. The gas control valve on the tank has its own off position, and that’s what you’ll use. Shutting off the main line is overkill and adds another step where something can go wrong.

Step 1: Locate the Gas Control Valve and Pilot Assembly

The gas control valve is the box-shaped unit on the front of the tank, usually near the bottom. It has a large knob with positions labeled “Off,” “Pilot,” and “On.” Below or beside the knob, you’ll find a small red or black button—that’s the reset button, also called the piezo igniter on some models. The pilot tube is a thin copper line that runs from the valve into the burner compartment.

If your Rheem is a newer model with electronic ignition, you’ll see a small window with a status light instead of a manual piezo button. The light blinks in specific patterns to indicate error codes. You’ll need to know what those codes mean, but for now, just locate the light and the gas control knob.

Take the flashlight and look inside the burner access panel. You should see the pilot tube and a small burner assembly. The pilot flame, when lit, sits at the end of that tube. If you can’t see it clearly, you may need to remove the access panel. On most Rheem units, it’s held by a single screw at the bottom or just snaps off.

Step 2: Turn the Knob to “Off” and Wait 10 Minutes

This is the step most people skip, and it’s the one that causes the most trouble. Turn the gas control knob to the “Off” position. Press down slightly if it doesn’t turn—some Rheem valves require you to depress the knob before rotating it. Once it’s off, wait. Set a timer for ten minutes. Do not shorten this. The wait lets any gas that has accumulated in the combustion chamber dissipate completely.

Why ten minutes? The combustion chamber is a sealed space, and gas is heavier than air. It pools at the bottom and takes time to clear. If you try to light the pilot immediately after turning the gas off, you’re risking a small explosion—the gas ignites in a puff, and you get a face full of hot air and soot. I’ve seen it happen. It’s not catastrophic, but it’s scary and it can damage the igniter.

While you’re waiting, take a good look at the gas control valve. Is there any corrosion or obvious damage? Is the knob cracked? If the valve looks worn, that’s a sign you might need a professional. A faulty gas valve is not something to patch up with duct tape.

Step 3: Switch the Knob to “Pilot” and Depress the Reset Button

After the ten minutes are up, turn the knob to the “Pilot” position. Now, press and hold the reset button. On older Rheem models, this is a separate button near the knob. On some newer ones, you push the knob itself down. Hold it down firmly. This does two things: it opens the gas valve so gas flows to the pilot tube, and it sends a signal to the thermocouple or flame sensor that you’re trying to light the pilot.

Keep holding the button down. Do not release it yet. If you let go before the pilot is lit and the thermocouple has warmed up, the gas supply shuts off immediately. That’s the safety mechanism working as designed, but it means you’ll have to start over.

For electronic ignition models, the sequence is slightly different. You’ll turn the knob to “Pilot” and press the igniter button, which is often the same as the reset button. The status light will blink or turn solid to indicate the ignition sequence has started. Hold the knob down for about 30 seconds after the pilot lights to give the flame sensor time to register the flame.

Step 4: Ignite the Pilot Flame

With the reset button still depressed, bring your long-stemmed lighter to the pilot tube. You should see the end of the tube clearly now. Push the lighter’s spark or flame directly at the pilot tube opening. The pilot should light with a small blue flame. If it doesn’t light within a few seconds, stop. Release the reset button, turn the knob back to “Off,” and wait another five minutes before trying again. You don’t want to keep feeding gas into the chamber while you’re fumbling with the lighter.

If you’re using a piezo igniter (the button that clicks), you’ll press that button instead of using a lighter. You’ll hear a clicking sound as it sparks. Some Rheem models have the piezo built into the gas valve; others have a separate red button. If the piezo doesn’t produce a spark, you can use a manual lighter as a backup—the piezo is a convenience, not a requirement.

Once the pilot is lit, keep holding the reset button down for a full 30 to 60 seconds. This is the critical part. The thermocouple or flame sensor needs time to heat up and generate a small electrical current that holds the gas valve open. If you release too early, the pilot goes out and you start over. Count to thirty slowly. If you’re impatient, count to sixty. The extra time costs you nothing.

Step 5: Release the Button and Turn the Knob to “On”

After holding the reset button for a minute, release it. The pilot flame should stay lit on its own. If it goes out immediately, you’ve got a thermocouple problem, which I’ll cover in the troubleshooting section. If it stays lit, turn the gas control knob from “Pilot” to “On.” You should hear the main burner ignite within a few seconds as the thermostat calls for heat. That’s the sound of success—a soft whoosh as the burner lights.

Now, replace the access panel and set the thermostat to your desired temperature. Most households use 120°F (49°C) for a good balance of comfort and safety. If you’ve had the tank off for a while, it will take some time to heat up. Expect to wait 30 to 60 minutes for a full tank of cold water to reach temperature.

One thing to watch: if the burner makes a loud boom or a popping sound when it lights, that’s a sign of delayed ignition. That means gas is accumulating in the burner chamber before the spark ignites it. This is a serious problem, often caused by a dirty burner or a faulty igniter. Turn the unit off and call a professional.

Troubleshooting: Why the Pilot Light Keeps Going Out

You’ve relit the pilot, it stays on for a day, and then it’s out again. This is the most common service call in the water heater world. Before you call a plumber, here are the three things you can check yourself.

Checking the Thermocouple

The thermocouple is a copper tube that runs from the gas valve to the pilot flame. It’s a safety device that generates a tiny electrical voltage when heated. If that voltage drops, the gas valve closes and kills the pilot. Over time, the thermocouple gets coated with soot, or the connection at the gas valve loosens. Both cause the pilot to go out.

To check it, first make sure the connection at the gas valve is tight. It’s usually a brass nut that you can tighten with an adjustable wrench. Don’t overtighten—snug is enough. If that doesn’t fix it, look at the tip of the thermocouple where it sits in the pilot flame. It should be clean and shiny. If it’s black or crusty, you can clean it with fine sandpaper, but honestly, replacing it is easier. A new thermocouple costs about $15 and takes ten minutes to install. It’s a standard part, and you can find it at any hardware store.

One more thing: the thermocouple must be positioned so the pilot flame wraps around the tip. If the pilot flame is too small or pointed away from the thermocouple, it won’t heat up enough. Adjust the pilot flame if your valve has an adjustment screw, or reposition the thermocouple bracket.

Resetting the Thermal Switch (ECO)

Rheem water heaters have a thermal switch, also called a spill switch or ECO (energy cut-off). It’s a small disc-shaped device with two wires attached, located near the burner access. This switch trips if the flue gets too hot, which can happen if there’s a downdraft or a blocked vent. When it trips, it cuts power to the gas valve, which kills the pilot.

If your pilot won’t stay lit and the thermocouple checks out, look for this switch. It has a small red reset button in the center. Press it firmly until you feel a click. Then try relighting the pilot. If the switch trips again, you have a ventilation problem, not a switch problem. The flue may be partially blocked, or the draft hood is installed incorrectly. That’s a job for a professional.

Don’t be tempted to bypass the ECO by removing it. That switch is there to prevent a carbon monoxide hazard. If it keeps tripping, something is genuinely wrong with your venting, and you need to fix the root cause, not disable the safety.

How to Identify a Healthy Pilot Flame

When the pilot is lit, take a look at the flame. A healthy pilot flame is blue with a distinct blue inner cone and a sharp blue tip. It should be steady, about half an inch to an inch tall, and it should wrap around the thermocouple tip. That blue color means complete combustion—the gas is burning cleanly.

A yellow or orange flame is a warning sign. It means incomplete combustion, which produces carbon monoxide. This can be caused by a dirty pilot tube, a partially blocked air inlet, or a gas pressure problem. A small amount of yellow at the very tip is sometimes normal, but if the whole flame is yellow or if it’s flickering and dancing, shut the unit down and call a professional. Don’t mess with this. Carbon monoxide is odorless and deadly.

Also listen to the burner when it kicks on. A clean burner produces a steady, low roar. If you hear popping, rumbling, or a fluttering sound, the burner is likely dirty or the gas mixture is wrong. Both need professional attention.

When to Call a Professional Plumber

You’ve tried the steps above, and the pilot still won’t light, or it lights and goes out repeatedly. At some point, you have to accept that this is beyond a DIY fix. Call a licensed plumber or a gas appliance technician if you encounter any of these:

• You smell gas persistently, even after waiting and trying to relight.
• The gas control valve is cracked, corroded, or visibly damaged.
• The pilot flame is yellow or orange after cleaning the pilot tube.
• The burner makes loud popping or rumbling sounds when it lights.
• The ECO switch keeps tripping after you reset it.
• You’ve replaced the thermocouple and the pilot still won’t stay lit.

A professional will have a manometer to check gas pressure, a combustion analyzer to verify safe operation, and the experience to diagnose issues that aren’t obvious. The cost of a service call is worth it compared to the risk of carbon monoxide poisoning or a gas explosion. Don’t be a hero.

Rheem-Specific Variations: Manual vs. Electronic Ignition

Rheem has made both types of gas valves over the years, and the procedure differs. If your tank has a simple knob and a separate red button, you have a standing pilot with a thermocouple. Follow the steps above exactly.

If your tank has a small window with a status light and a digital display, you have an electronic ignition model. These don’t use a thermocouple—they use a flame sensor and an electronic control board. The relight procedure is similar, but you’ll hold the knob down and press the igniter button, then watch the status light. A solid green light usually means the pilot is lit and the system is working. A blinking red light indicates an error code. Check the label on the side of the tank for a code chart.

Electronic ignition models are more efficient because they don’t waste gas on a standing pilot. But they’re also more complex. If the status light shows an error code you can’t find in the manual, that’s a clear sign to call a pro. The control board is not a user-serviceable part.

Comparison: Relight Methods by Valve Type

Feature	Manual Standing Pilot	Electronic Ignition
Ignition method	Piezo spark or manual lighter	Automatic spark from control board
Safety sensor	Thermocouple	Flame sensor (electronic)
Relight procedure	Hold reset button, light pilot, wait 30-60 sec	Turn to pilot, press igniter, watch status light
Common failure point	Thermocouple wears out	Control board or flame sensor
User-replaceable parts	Thermocouple, igniter	Usually none; requires technician
Pilot flame when not in use	Always burning	Burns only when needed

That table sums up the key differences. If you have an older unit, you can fix most issues with a $15 thermocouple. If you have a newer unit, the troubleshooting is more limited, and you’ll likely need a service call for anything beyond a simple relight.

Frequently Asked Questions

Why does my Rheem water heater pilot light keep going out?

The most common cause is a faulty thermocouple. It’s a safety device that senses the pilot flame and keeps the gas valve open. If it’s dirty, worn out, or not positioned correctly in the flame, it won’t generate enough voltage, and the valve shuts off. Replace it if cleaning and tightening don’t help. The second most common cause is a tripped thermal switch (ECO), which you can reset with a small button. If the switch trips repeatedly, you have a venting issue.

Can I relight the pilot light without turning off the gas?

No. You must turn the gas control knob to the “Off” position and wait at least ten minutes before attempting to relight. This allows any accumulated gas in the combustion chamber to dissipate. Skipping this step is how you get a face full of flame. The ten-minute wait is non-negotiable.

What does the reset button on my Rheem water heater do?

There are two different buttons. The one near the gas valve, often red or black, is the piezo igniter—it creates a spark to light the pilot. The one on the thermal switch, usually a small disc near the burner access, is the ECO reset. The piezo igniter is used during the relight process. The ECO reset is only used when the thermal switch has tripped due to overheating or a vent blockage.

How do I know if my Rheem water heater has electronic ignition?

Look for a small window with a status light on the gas control valve. Electronic ignition models have a visible LED that blinks or turns solid during operation. They may also have a digital temperature display. Older models with a standing pilot have a simple knob and a separate red igniter button, with no status light.

Is it safe to relight the pilot light myself?

Yes, if you follow the safety rules. Turn the gas off, wait ten minutes, and don’t attempt it if you smell gas. Use a long-stemmed lighter to keep your hands away from the flame. If you have any doubt about your ability, or if the unit shows signs of damage, call a professional. It’s a simple job, but it involves gas, so respect it.

What to Remember Next Time

• Turn the gas control knob to “Off” and wait a full ten minutes before relighting. Never skip this.
• Hold the reset button down for 30 to 60 seconds after the pilot lights to give the thermocouple time to warm up.
• A blue flame with a sharp tip is healthy. A yellow or orange flame means incomplete combustion—call a pro.
• If the pilot won’t stay lit, check the thermocouple first, then the thermal switch (ECO).
• If you smell rotten eggs, leave the house, don’t touch any switches, and call your gas utility.
• Keep the area around the water heater clear of flammable items.
• When in doubt, call a licensed plumber. A service call is cheaper than a hospital visit.

Relighting a pilot light is one of those small home maintenance tasks that seems intimidating until you’ve done it once. Now you know the exact steps, the safety protocols, and what to do when things go sideways. Your Rheem tank will be back to producing hot water before you finish your first cup of coffee. For more detailed guidance on your specific model, check out this Rheem pilot light guide or this step-by-step lighting tutorial. If you’re dealing with a recurring issue, this restart troubleshooting resource covers additional fixes.