On a Rheem gas water heater, one blink every three seconds is normal. Two blinks means low thermopile voltage. Four means the high temperature limit tripped, five a temperature sensor failure, seven a gas control failure and eight a false pilot flame signal. Newer models add nine and ten for chamber faults.
How do I read the status light on a Rheem?
Count the blinks in one cycle. Rheem's manual says one blink every three seconds is normal. Longer or extra blinks are a code. The pilot has to be lit for the light to report anything. Rheem's notice says the pilot burner must be lit to view status light codes, and that if the pilot lights but will not stay lit after you release the knob, you should repeat the lighting steps and keep the knob pressed until the pilot is lit and the code can be read.
Newer Rheem manuals add color. A blue blink means normal operation, and a red blink means a system problem. The older manual has one color and reads the count only.
What does each Rheem blink code mean?
This table follows Rheem's Use and Care manuals, the current one and the older one.
| Blinks | What Rheem says it means | What to do |
|---|---|---|
| Light off | Gas control turned off, pilot not lit, or not enough thermopile power | Follow the lighting instructions on the tank. Check the thermopile connector and wires. Inspect the pilot assembly. |
| Steady on | Pilot recently went out and the thermopile is cooling, or the knob was just turned to OFF | Wait, then follow the lighting instructions. |
| 1 blink | Normal operation | Set the knob to your temperature. |
| 2 blinks | Low thermopile voltage, but the pilot is lit | Check the thermopile connector at the gas control, check the wires for damage, inspect the pilot assembly. |
| 4 blinks | High water temperature limit tripped | Contact a qualified service technician. |
| 5 blinks | Water temperature sensor failure | Contact a qualified service technician. |
| 7 blinks | Gas control (thermostat) failure | Contact a qualified service technician. |
| 8 blinks | False pilot flame signal | Contact a qualified service technician. |
| 9 blinks | Chamber sensor failure (newer models) | Contact a qualified service technician. |
| 10 blinks | Chamber temperature shutdown (newer models) | Contact a qualified service technician. |
Rheem's manual says the same thing about the safety devices in general: do not attempt repair of gas piping, the gas control, burners, the venting system or other safety devices. Refer them to qualified service personnel.
Which codes can I safely handle myself?
Two of them, and only as far as the manual goes. Light off and steady on are lighting problems. Follow the lighting instructions printed on your tank. Rheem's lighting steps have you turn the knob to PILOT, hold it in, press the spark button several times until the status light starts to blink, and confirm the flame through the sight glass. If the light does not blink within 90 seconds and the pilot will not stay lit after several tries, Rheem says to turn the knob to OFF and call your service technician or gas supplier. If the knob does not pop back out when released, stop and call right away.
A 2 blink code is the other one. It says the pilot is lit but the thermopile, the small part that makes the power for the gas valve, is not producing enough voltage. Rheem's checks are all visual: make sure the thermopile connector is firmly attached to the gas control, look at the wires for damage, and inspect the pilot assembly. If the wires look fine and the code stays, a technician can measure the thermopile output with a meter. A.O. Smith's service handbook for a similar gas valve uses 350 millivolts DC as the point below which the thermopile should be replaced, but check the exact figure for your model with a technician.
Everything from four blinks up is a technician call by Rheem's own chart. That is not a sales line. Those codes cover a temperature sensor, a gas control and the safety circuit, and none of it is a DIY part.
### What should I write down before I call?
A little prep makes the visit faster. Rheem's manual says to give the model and serial number from the rating plate when you order parts, and the same details help a technician bring the right gas control. Write down these items:
- The blink count and whether the light is blue or red, if your model shows color.
- The model and serial number from the rating plate on the side of the tank, and the gas type printed there, natural gas or propane.
- When it started. After a power problem, a storm, a gas interruption, or new work near the heater, or out of nowhere.
- Whether the pilot stays lit when you release the knob.
- Whether any other gas appliance is acting up.
Take a phone video of the light for one full cycle. Counting blinks by eye is easy to get wrong, and a video lets you check the count twice.
What about a gas smell or a locked-out heater?
If you smell gas at any point, leave the house. Rheem's manual is clear: do not light any appliance, do not touch a switch or phone inside, and call the gas supplier from a neighbor's phone. If you cannot reach them, call the fire department. In the Phoenix area, Southwest Gas takes calls at 877-860-6020, and 911 works for any suspected leak. See what to do when the pilot is out and you smell gas for what comes after that call.
Rheem also notes that its water heaters include a combustion shut off device. It shuts the heater down if flammable vapors show up or if the combustion air inlet is blocked. If your pilot lights but the main burner will not stay lit, the manual lists a tripped combustion shutoff system as a cause and tells you to contact a qualified service technician. Rheem warns against storing gasoline or other flammable vapors and liquids near the heater, so move any out of the room before the technician arrives. Keep the combustion air inlet openings at the base clear too, since Rheem says blocking them can shut the heater down.
If the main burner keeps shutting off and no blink code explains it, our page on why a gas water heater keeps shutting off covers the thermal switch, the flame arrestor and the air supply.
When should I call a plumber for a Rheem blink code?
Call for any code from four blinks up, for a 2 blink code that stays after a look at the connector and wires, and for a pilot that will not stay lit after several lighting attempts. Also call if the same code keeps returning, since a heater that trips its temperature limit is telling you something about the gas control or the temperature sensor.
HQ Plumbing and Air is licensed and insured and takes emergency calls 24/7. A visit starts with a free estimate and an upfront price, so a gas control diagnosis has no surprises.
If your pilot dies as soon as you let go of the knob, our page on why a water heater pilot light will not stay lit covers the thermocouple and the other usual causes. If you own an A. O. Smith, see our page on A. O. Smith water heater blinking light codes, which covers a similar gas valve with slightly different codes. Tank sediment is a separate Phoenix issue: hard water builds it up over time, and our page on how often to flush a water heater in Phoenix gives the schedule.
Bradford White uses a similar gas valve light. See our page on Bradford White flashing light codes.