The short answer
A Rheem gas water heater in Northern Virginia blinks to tell you what’s wrong, and the same count means different things on different tanks. On a standing pilot tank, one blue blink every three seconds is normal, two red blinks means the pilot isn’t making enough voltage, and four or more red blinks is a call. On a power vent tank, the count is a fault code, and seven flashes usually means the tank smelled something flammable nearby. So the first job is knowing which tank you have.
Which tank do you have?
- Standing pilot: a gas knob, a spark button and a little window to see the pilot flame. No power cord. The light sits on the gas control.
- Power vent: a fan on top of the tank, a plastic vent pipe and a power cord. If the fan isn’t running, the burner won’t light.
- Flue damper: a motorized flap in the metal flue pipe on top and a power cord.
- A row of lettered lights instead of one blinking light: that’s a hot surface ignitor model, and the pattern of lit lights is the code. The chart is in its manual.
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Standing pilot tanks: the status light
The pilot has to be lit to read the light. If it won’t stay lit, hold the knob in while you count.
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| Light | What Rheem says it means | What to do |
|---|---|---|
| Off | Pilot out, knob off, or too little voltage | Relight with the steps on the label |
| Constantly lit | The pilot just went out and the probe is cooling | Wait, then relight |
| 1 blue blink every 3 seconds | Normal: pilot lit | Turn the knob to your temperature |
| 2 red | Thermopile voltage low | Relight once; if it repeats, call |
| 4 red | High temperature shutdown | Call |
| 5 red | Temperature sensor failure | Call |
| 7 red | Gas control failure | Call |
| 8 red | Flame sense error | Call |
| 9 red | Chamber sensor failure | Call |
| 10 red | Chamber temperature shutdown | Call |
There’s no 3 or 6 on this light. If you counted one of those, count again from the start of a pause.
Two red blinks: the thermopile
The thermopile is the probe that sits in the pilot flame and makes the small amount of electricity the gas control runs on. Two red blinks means it’s lit but weak: a dirty pilot, a probe wearing out, or a loose connector where its wire plugs into the control. Our thermocouple guide covers the older cousin of the same part, and our pilot keeps going out guide walks through the usual causes.
Relighting it, Rheem’s way
- Turn the knob to OFF and wait five minutes.
- Turn it to PILOT, push it all the way in and press the spark button until the status light blinks.
- Look through the window to see the flame, put the outer door back, then let go of the knob.
- Turn the knob to the temperature you want.
If the light doesn’t blink after 90 seconds and the pilot isn’t lit, start over. If it won’t stay lit after a few tries, turn it off and call. Our pilot lighting guide has the photos, and Rheem pilot light help covers the older Rheem tanks. If you smell gas, don’t flip any switches: leave the house and call your gas company or 911 from outside.
Power vent tanks: flash count and display code
A short flash every four seconds means the tank is idle and waiting. A heartbeat flash means it’s heating. Anything else is a code, and tanks with a display show a number for the same fault.
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| Flashes | Display | What it means |
|---|---|---|
| 1 | 12 | Weak flame signal |
| 2 | 44 | Pressure switch stuck closed |
| 3 | 46 | Pressure switch open: a blocked vent, a bad fan or a pinched hose |
| 4 | 31 | Thermal cutoff open |
| 5 | 14 | Flame where there shouldn’t be one |
| 6 then 1 | 11 | Failed to light |
| 6 then 2 | 45 | Too many restarts |
| 6 then 3 | 13 | Flame lost too many times |
| 6 then 4 | 14 | Flame sensed out of sequence |
| 6 then 5 | 10 | Hard lockout |
| 7 | 47 | Flammable vapor sensor tripped |
| 8 then 1 | 49 | Flammable vapor sensor fault |
| 8 then 2 | 89 | Water temperature sensor |
| 8 then 3 | 15 | Electronics |
| 8 then 4 | 93 | Gas valve |
On display models, holding all the buttons for five seconds shows the last nine alarms, which is worth a photo before anyone clears them.
Resetting a power vent tank
- Turn the knob all the way clockwise.
- Unplug the tank for a few seconds and plug it back in.
- Swing the knob back and forth across the middle mark seven times.
- Listen for the fan on top to start.
- Set the temperature to 120F or lower.
Do that once, and skip it after seven flashes. If it locks out again, the cause is still there. Our power vent photos show the fan and vent to look at.
Flue damper tanks
Swipe to see all columns →
Swipe to see all columns →
| Flashes | What it means |
|---|---|
| 1 | Weak flame |
| 2 | Damper switch stuck closed |
| 3 | Damper switch open: the damper didn’t open |
| 4 | Thermal cutoff open |
| 5 | No flame sensed |
| 6 then a number | A lockout |
| 7 | Flammable vapors: move them out, air the room, leave the switch alone and call |
| 8 then a number | A fault in the control or a sensor |
| 9 | Chamber sensor |
| 9 then 2 | Chamber temperature |
Seven flashes means two different things
On a power vent or damper tank, seven is the flammable vapor sensor. Gas cans, paint thinner, solvent or a spilled can of anything near the tank will set it off. Move them out, open a window and call. Rheem’s power vent manual says not to touch the heater’s switch after this one. On a standing pilot tank, seven red blinks is the gas control itself failing, and that one is a replacement part.
Safe checks
- Count twice, from the start of a pause.
- Power vent and damper tanks: is it plugged in, and does the outlet work?
- Walk outside and look at the vent: snow, leaves or a nest can block it.
- Clear anything flammable away from the tank.
What not to do
Don’t keep relighting a pilot that won’t stay lit, don’t cover or bypass the vapor sensor, and don’t take the gas control apart. Don’t turn the temperature up to fix lukewarm water, either. If your carbon monoxide alarm goes off, get everyone outside first and read our CO alarm guide from there.
What a technician does
We measure the thermopile’s voltage, clean the pilot, check the vent, fan and pressure switch, read the alarm history and test the sensor the code points at. You get the price before we fix anything. While we’re there, the water heater flush is $99 (normally $199): we drain and flush the tank, check the anode rod and test the relief valve. If the tank is past ten years old, putting money into a new control rarely pays back: the water heater estimator shows the installed price of a new tank, and $500 comes off it.
Related: Rheem water heater troubleshooting, water heater blinking light, every brand, how old is my Rheem, A. O. Smith codes, Bradford White codes and our error codes guide.
Every code meaning here comes from Rheem’s own documents: gas water heater Use and Care manual, Low NOx gas manual, power vent bulletin TB 1627, power vent manual, flue damper manual and hot surface ignitor manual.
Call or book
A plumbing diagnosis visit is $49, or $250 after hours, and you get the price of the fix before we start. Call (703) 997-9757, day or night, and tell us the code, or book the water heater flush from goswiftpro.com/cookiesoffer by November 30 and a box of warm MOLTN cookies comes with it. Every current deal is on our offers page. Rated 5.0 stars across 1,138 reviews on Google, Angi, Yelp, the BBB and Facebook, Virginia Class A license 2705192276.
Questions people ask
Why is my Rheem water heater blinking red 2 times?
On a standing pilot tank, two red blinks means the thermopile voltage is low: the pilot is lit but weak. Relight it once. If it comes back, the pilot or thermopile needs service. On a power vent tank, two flashes means the pressure switch is stuck closed.
Is a blinking blue light on a Rheem water heater normal?
Yes. One blue blink every three seconds means the pilot is lit and the tank is working.
What does 7 blinks mean on a Rheem water heater?
On a power vent or flue damper tank, the flammable vapor sensor tripped: move anything flammable away, air the room, leave the heater’s switch alone and call for service. On a standing pilot tank, it means the gas control failed and needs replacing.
How do I reset a Rheem power vent water heater?
Turn the knob fully clockwise, unplug it for a few seconds, swing the knob across the middle mark seven times and listen for the fan. Skip this after seven flashes, and if it locks out again, call for service.
