How to Light a Rheem Hot Water Heater in 7 Steps
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You walk into the shower first thing in the morning, turn the handle, and get nothing but ice. The water heater pilot light went out overnight. It happens. And if you own a Rheem gas water heater, getting that pilot relit is something you can do yourself — no need to call a plumber or wait all day.
This guide walks you through the exact procedure, from safety checks to the final flame. You will know what tools you need (almost none), what to do when the thermocouple is bad, and how to avoid common mistakes that keep the pilot from staying lit. Follow these seven steps in order and you will have hot water again inside 15 minutes.
The Rheem UV11698 Upper Thermostat is a common replacement part for electric models, but if you are working on a gas Rheem water heater and the pilot won’t stay lit, the thermocouple or gas control valve is usually the culprit — not the upper thermostat. That said, if you own an electric Rheem and the water isn’t heating, a faulty upper thermostat could be the problem. The Rheem UV11698 is a direct replacement for many Rheem electric units. You can Check price on Amazon if you suspect your thermostat needs swapping.
Safety First – What You Need Before Touching Anything
Gas and water together make a dangerous pair if you rush. Before you touch any knob or button, do these three things.
Turn the gas supply off at the heater. There is a gas shutoff valve on the pipe leading into the water heater. Usually it is a small lever or knob. Turn it so the handle is perpendicular to the pipe — that means gas is off. Wait five minutes for any lingering gas to clear. This step is not optional. If you smell gas after waiting, stop and call a professional.
Gather your tools. You need a flathead screwdriver (to remove the access panel and burner cover), a flashlight or headlamp, and maybe a long-reach lighter if your heater does not have a piezo igniter. Some Rheem models have a red button that generates a spark. Others require you to light the pilot manually with a lighter or match.
Know your model. Rheem makes both standing pilot models and electronic ignition models. The standing pilot has a gas control valve with a knob labeled OFF, PILOT, and ON. The electronic ignition model has a small window and a igniter button. The steps below cover the standing pilot — the most common type in older Rheem units. If you have an electronic ignition, the process is slightly different; see the FAQ at the end.
The 7-Step Lighting Procedure
These steps assume you have a standing pilot Rheem gas water heater. Work slowly. If anything feels wrong, stop and get help.
- Set the gas control knob to OFF. Push the knob down slightly and turn it to OFF. You will hear a click. Wait at least five minutes for any gas in the chamber to dissipate. Use this time to remove the outer access panel and the inner burner cover.
- Locate the pilot assembly. Inside the burner compartment you will see a small tube (the pilot tube) ending in a tiny nozzle. Next to it is the thermocouple — a copper rod that senses the pilot flame. The pilot flame should hit the tip of that rod. If the rod is bent or dirty, the pilot won’t stay lit.
- Turn the gas control knob to PILOT. Push the knob down and hold it. This opens the gas valve to the pilot tube only. Keep holding it down for the next step.
- Light the pilot. If your heater has a red piezo igniter button, press it repeatedly while holding the knob down. You should see a small blue flame appear at the pilot nozzle. If you do not have a piezo button, use a long-reach lighter or a match on a wire holder to light the pilot. Keep holding the knob down for 30 to 60 seconds after the flame ignites. This gives the thermocouple time to heat up and signal the gas valve to stay open.
- Release the knob slowly. If the pilot stays lit, good. If it goes out, you did not hold it long enough, or the thermocouple is weak. Try again and hold for a full 60 seconds. If it still does not stay, the thermocouple may need replacing — a $10 part and a 10-minute job.
- Turn the gas control knob to ON. Once the pilot stays lit, turn the knob from PILOT to ON. Do not push down while turning. You should hear the main burner fire up within a few seconds. Check that the flame is blue with a small yellow tip. A yellow or orange flame means incomplete combustion — turn everything off and call a technician.
- Replace the covers and restore power. Put the inner burner cover and the outer access panel back. Fasten screws. Turn the gas supply valve back on (handle parallel to the pipe). If your unit has an electrical connection, plug it back in or flip the breaker. Set the thermostat to your desired temperature — usually 120°F is a safe default.
That is it. You should have hot water after the burner runs for ten to fifteen minutes.
When the Pilot Won’t Stay Lit – Common Troubleshooting
Pilot goes out a few seconds after you release the knob? That is almost always a thermocouple issue. The device is a safety sensor that generates a small electrical current when heated. If it is dirty, bent, or worn out, the gas valve thinks the pilot is off and shuts the gas. Clean the tip of the thermocouple with fine sandpaper or steel wool. If that does not fix it, replace the thermocouple. It screws into the gas control valve and costs very little.
Another possibility: the gas control valve itself is failing. This is less common but can happen on older units. Look for signs like the knob feeling loose, or the pilot staying lit but the main burner not firing. Replacing the gas valve is a job for a pro, as it involves gas line work.
If you are working on an electric Rheem water heater and it is not heating, the upper thermostat might need replacing. The restart gas water heater procedure for electric models is different — you will reset the high-limit switch and check the thermostat continuity. A faulty thermostat can trip the high-limit and kill power to the elements. The Rheem UV11698 we mentioned earlier fits many Rheem electric models and is a common fix.
Water Heater Owner's ToolkitFix the common faults yourself, keep it running for years, and know when a repair is money wasted.No-hot-water flowcharts, gas and electricFlush, anode, relief valve and descaling stepsRepair-or-replace calculator (Excel)Standing Pilot vs Electronic Ignition: What Is Different?
Some newer Rheem models use an electronic ignition system. These do not have a standing pilot. Instead, a hot surface igniter or spark igniter lights the burner only when the thermostat calls for heat. You will not see a constant small flame. If the pilot goes out in these units, it usually means a failed igniter or a control board issue. The lighting procedure is different — you typically press a reset button or cycle the power. Check your owner’s manual.
| Feature | Standing Pilot Rheem | Electronic Ignition Rheem |
|---|---|---|
| Pilot flame visible all the time? | Yes, a small blue flame | No, only lights when needed |
| How to relight | Knob to PILOT, hold, ignite | Press reset or power cycle |
| Common failure point | Thermocouple or pilot orifice | Hot surface igniter or control board |
| DIY difficulty | Easy – most homeowners can do it | Moderate – may need multimeter |
If you are unsure which type you have, check the label on the side of the tank. It will say either “Standing Pilot” or “Electronic Ignition.” Also look for a red “PILOT” button — standing pilots have that.
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Frequently Asked Questions
Why does my Rheem water heater pilot keep going out after I relight it?
Most often it is the thermocouple. It might be dirty, bent, or worn. Clean it gently with sandpaper and make sure the tip sits directly in the pilot flame. If it still goes out after a minute, replace the thermocouple. Another cause is a draft blowing out the pilot flame — check that the burner cover is fully seated and there is no open window nearby.
Do I need to turn off the gas before lighting the pilot?
Yes. Always turn the gas valve to OFF and wait five minutes before attempting to light the pilot. This clears any gas that may have accumulated inside the combustion chamber. Skipping this step can cause a small explosion or flash fire.
Can I use a regular lighter to light the pilot?
You can, but a long-reach lighter or a fireplace match is safer. A standard cigarette lighter puts your hand inside the burner compartment, which is tight and can burn your fingers. Get a long-neck butane lighter designed for water heaters.
How do I know if the gas control valve is bad?
If the pilot stays lit (you kept the knob held for a full minute) but the main burner does not come on when you turn the knob to ON, the gas valve may be stuck or the thermostat may have failed. Try tapping the valve lightly with a screwdriver handle — sometimes it frees a stuck diaphragm. If that does not work, call a technician. Gas valve replacement requires shutting off the main gas line and testing for leaks.
My Rheem water heater is electric — does this lighting procedure apply?
No. Electric water heaters have no gas or pilot flame. If your electric Rheem is not heating, check the breaker, the high-limit reset button, and the upper and lower thermostats. The light a Rheem gas water heater steps are for gas models only. For electric models, the most common fix is replacing a failed thermostat or heating element.
What To Remember Next Time the Pilot Goes Out
- Turn gas off and wait five minutes before doing anything else. Safety is faster than a trip to the ER.
- Hold the knob down for a full minute after lighting the pilot. Most relight failures are from rushing this step.
- Keep a spare thermocouple on hand. It costs about $10 and fixes 90% of pilot problems.
- Clean the pilot orifice if the flame looks weak or yellow. Use a needle or compressed air.
- Replace the access panel and burner cover before turning the gas back on. Those covers keep drafts out and contain any flame.
- If the main burner flame is yellow or orange, shut everything off and call a pro. That means incomplete combustion and carbon monoxide risk.
- Write down your Rheem model number now. It is on a sticker on the side of the tank. You will need it if you buy replacement parts or call technical support.
