You step into the shower. Ice water. The pilot light is out on your Rheem gas water heater, or the electric one just stopped heating. Panic sets in. Before you call a plumber and spend $200 on a service call, know this: most Rheem water heater restarts are simple, safe, and take under ten minutes. But one wrong move — like flipping the breaker on and off five times — can damage the control board.
This article gives you the exact instructions on restarting Rheem water heater models, gas and electric. I’ll cover the reset button, error codes, the sequence of steps, and the common myths that cause people to mess it up. No fluff. No ‘try this generic tip.’ Just what works for Rheem.
You’ll walk away knowing when to press that little red button, when to relight the pilot, and when to stop messing with it and call a pro.
The Big Myth: ‘Just Reset the Breaker’ — Why That Often Fails
Most people think a Rheem water heater restart is the same as rebooting a router. Flip the breaker off, wait two minutes, flip it on. That works about 60% of the time — when the issue is a temporary power surge or a stuck limit switch.
But Rheem electric water heaters have a separate high-limit reset button. It’s a small red button on the thermostat behind the access panel. If the water got too hot (over 180°F) or a sensor tripped, flipping the breaker does nothing. You have to manually push that reset button.
Here’s the catch: if the limit tripped because of a real problem — like a bad thermostat or sediment buildup — pushing the button restarts water heating temporarily, but it’ll trip again within hours. That’s a symptom, not the fix.
So the first thing to check: is the water cold and did you hear any clicking or see an error code? If yes, skip the breaker and go straight to the reset button.
Gas Rheem Units: The Pilot Light Isn’t Always Dead — Sometimes It’s a Safety Switch
Another myth: ‘If the pilot light won’t stay lit, the thermocouple is bad.’ That’s true on old models. But Rheem gas water heaters built after 2026 use a smart valve system. When the pilot blows out, the gas valve locks itself out for safety. You can’t just click a button. You must follow a specific sequence.
Here are the actual instructions on restarting Rheem gas water heaters with a Honeywell or White-Rodgers gas valve:
- Turn the gas control knob to OFF. Wait 5 minutes to clear any gas that might have leaked.
- Turn the knob to PILOT. Push it down and hold it.
- While holding the knob down, press the igniter button repeatedly until the pilot flame appears. Keep holding the knob down for 30 seconds after ignition.
- Release the knob. If the pilot stays lit, turn the knob to ON. The burner should fire up within a minute.
If the pilot lights but goes out when you release the knob, the thermocouple might be failing. But don’t replace it yet. First, check for a blocked vent or a draft that blows out the flame. Also, clean the pilot orifice with compressed air — rust dust can clog it. I’ve fixed three Rheem units by blowing out spider webs from the pilot tube.
Electric Rheem Units: The Reset Button Is Not a Reset Button — Sort Of
Rheem electric water heaters have two reset buttons: one on each thermostat (upper and lower). Both are behind access panels. The upper thermostat has a red ‘reset’ button. The lower one has a black or red button. Pushing them does not ‘reset’ the heater’s memory — it simply re-closes the internal high-limit switch that tripped open.
If you push the upper reset button and hear a click but no heating resumes within 10 minutes, the problem is likely a failed thermostat or element. Don’t keep pressing the button. That can arc and weld the contacts shut, creating a fire hazard. Yes, it’s rare, but I’ve seen it.
Here’s the step-by-step for electric Rheem:
- Turn off power at the breaker. Do not just flip the breaker — pull the fuse or lock out the breaker with tape.
- Remove the upper access panel. Push the red reset button firmly.
- Replace the panel. Turn power back on. Wait 15 minutes. If no hot water, do the same for the lower thermostat.
- If still no heat, test the elements with a multimeter. Expect 10–16 ohms for a working element. Open or infinite ohms = dead element.
Do not test elements with power on. And watch the voltage rating: Rheem uses 240V elements, not 120V. Mix them up and you’ll get lukewarm water.
Rheem Error Code: One Flash, Two Flashes — What They Actually Mean
Newer Rheem water heaters with electronic control boards flash an LED error code. One flash often means ‘ignition failure’ on a gas unit. Two flashes mean ‘flame sensed when it shouldn’t be’ — that’s a stuck gas valve. Three flashes: thermal switch open.
People see one flash and immediately try to restart. But the correct fix for a one-flash error on a Rheem gas unit is to purge air from the gas line first. If your gas water heater has been off for a long time (or you had gas work done), air gets trapped in the pipe. That air prevents the pilot from lighting. Wait 60 seconds between attempts — don’t keep cranking the igniter. That floods the combustion chamber and creates a bad smell.
For electric units, error codes are less common, but if the LED on the control board is off entirely, check for a blown fuse on the board (yes, there’s a glass fuse inside some Rheem models). You can replace it yourself if you know how to solder. Otherwise, replace the whole control board — part number is on the old board.
Table: Quick Reference for Restart Methods by Rheem Type
| Water Heater Type | Primary Restart Action | Common Misstep | When to Call a Pro |
|---|---|---|---|
| Gas (2026+) | Purge air, hold PILOT knob, press igniter, hold 30 sec | Not waiting 5 minutes after turning gas off | Pilot won’t stay lit after 3 attempts; gas smell persists |
| Gas (Pre-2026) | Push red reset button on gas valve (if equipped) | Skipping thermocouple check | Thermocouple replacement needed or vent blockage |
| Electric (Standard) | Reset thermostat high-limit (red button behind access panel) | Flipping breaker only, ignoring button | Button trips again within hours; no ohms on element |
| Electric (Hybrid/Heat Pump) | Cyclic reset – power off 5 minutes, then on | Not waiting for refrigerant pressure to equalize | Error code ‘E’ or ‘F’ – control board likely dead |
Five Real Questions People Ask About Restarting Rheem Water Heaters
How long should I wait after restarting before I get hot water?
Gas: about 10 minutes for the first burst (the burner runs until the tank temp hits the setpoint). Full recovery from cold takes 40-60 minutes. Electric: 15 minutes for first warm water, 1-2 hours for full tank. Test with your hand—don’t rely on a quick shower.
Can I restart my Rheem water heater if I smell gas?
No. If you smell gas near the heater, do not turn any switches or lights. Leave the building, call your gas company from outside. A restart could ignite the gas. Only attempt restart after the gas has been cleared by a professional.
Why does my Rheem water heater keep tripping the reset button?
Likely one of three things: a bad thermostat (replace it), a shorted heating element (check continuity), or severe sediment buildup that causes overheating at the top of the tank. Sediment requires flushing the tank — a job best done yearly anyway. If you’ve never flushed it, start there.
Do I need to drain the water heater before restarting?
Not for a simple restart. But if you’re replacing a thermostat or element, yes, drain below the level of the part you’re working on. For a pilot light restart, draining is unnecessary. For an electric restart with a tripped limit, no draining needed.
My Rheem water heater has no power at all — what do I check first?
The small GFCI outlet (if your unit uses one) can trip. Check the red test/reset button on the outlet itself. Also check your home breaker panel — not just the heater’s breaker, but any ‘water heater’ labeled breaker. If both are OK, the water heater’s internal fuse may be blown. Look for a clear glass fuse on the control board near the LED.
What to Do After You Restart — And When to Give Up
- Write down the model number and serial number (on the rating plate) before you touch anything. You’ll need them for parts.
- After a successful restart, run hot water at a faucet for 2 minutes to purge air from the lines.
- If the water comes out with a brown tint, you stirred up sediment. Flush the tank completely — connect a hose to the drain valve and run it to a floor drain or outside.
- Test the pressure relief valve after restart. Lift the lever briefly. If no water spits out, the valve is clogged and needs replacement.
- Reset buttons are a bandage, not a cure. If you restart the heater more than twice in a month, you have an underlying problem. Either replace the thermostat/element or call a plumber.
- On gas units, check the vent pipe for blockages every time you relight the pilot. A bird’s nest in the flue can kill you with carbon monoxide.
- If after two full restart attempts the heater still won’t light or heat, stop. You are wasting time and risking damage. Pay the $200 service call.
