Gas water heater status light blinking: what Rheem, A.O. Smith and Bradford White codes mean
32 status-light patterns for US gas tank water heaters, from the makers’ own manuals. One flash, then a pause, is normal on all three brands. 4 flashes is an overheat shutdown on all three. But the counts do not always agree: 6 flashes on a Bradford White means a water leak on its Resideo V1 control and a failed door temperature sensor on the Ultra Low NOx Resideo V2, and 9 or 10 flashes exist only on Rheem and Bradford White Low NOx models. Pick the brand and the count.
If you smell gas: do not light any appliance or touch any electrical switch, and call your gas supplier from a neighbor’s phone — every maker’s manual below says so first, and every page here prints the maker’s own lines before anything else.
Find it by what you see
32 patterns.
- Rheem Status light offThe combination gas control is turned off, or the pilot is not lit, so there is no millivolt power from the thermopile to light the status light.
- Rheem Status light on steadyThe pilot was recently put out and the thermopile is cooling down, or the temperature knob was recently turned to OFF.
- Rheem 1 blue blink every 3 secondsNormal operation: the pilot is lit.
- Rheem 2 red blinks every 3 secondsLow thermopile voltage, although the pilot is lit.
- Rheem 4 red blinks every 3 secondsThe high water temperature limit has tripped: the water got hotter than the control’s safety limit, and the heater has shut down.
- Rheem 5 red blinks every 3 secondsWater temperature sensor failure.
- Rheem 7 red blinks every 3 secondsThe combination gas control (thermostat) has failed.
- Rheem 8 red blinks every 3 secondsFlame sense error.
- Rheem 9 red blinks every 3 seconds (Low NOx models)Chamber sensor failure: the sensor that watches the combustion chamber has failed.
- Rheem 10 red blinks every 3 seconds (Low NOx models)Chamber temperature shutdown: the combustion chamber got too hot and the heater shut down.
- A.O. Smith Status light off (0 flashes)The pilot light is not lit, or there is not enough power (millivolts) from the thermopile to keep it lit.
- A.O. Smith Status light on solidThe pilot was lit but is now off, and the thermopile is still cooling down.
- A.O. Smith 1 flash every 3 secondsNormal operation: the pilot is lit and the gas control valve has not detected any problem.
- A.O. Smith 2 flashes, then a pauseInsufficient power (millivolts) reaching the gas control valve/thermostat from the thermopile.
- A.O. Smith 4 flashes, then a pauseHigh water temperature has activated the overheat sensor (State’s handbook calls it “temperature exceeded (ECO activated)”).
- A.O. Smith 5 flashes, then a pauseSensor failure: the temperature sensor in the gas control valve has failed.
- A.O. Smith 7 flashes, then a pauseGas control valve/thermostat failure (State’s handbook: “internal control failure”).
- A.O. Smith 8 flashes, then a pauseThis appears only after the gas control knob has been turned off: either the thermopile kept making power because it did not cool as quickly as expected, or the pilot kept burning because the pilot valve is stuck open.
- Bradford White LED off, not flashingMillivolt power is not present: the pilot is out, so the gas valve is not powered. (3 meanings, by gas control)
- Bradford White 1 flash, then a pause of 3 to 4 secondsNo fault. (3 meanings, by gas control)
- Bradford White 1 flash every secondNot an error: the main valve is open and the main burner is lit, heating the water. (2 meanings, by gas control)
- Bradford White 2 quick flashes (a strobe), then a pauseNo fault: the thermostat is calling for heat and the water heater is operating normally.
- Bradford White LED on steadyThe set point knob has recently been turned to OFF. (3 meanings, by gas control)
- Bradford White 2 flashes, then a 3-second pauseWeak pilot flame detected. (3 meanings, by gas control)
- Bradford White 3 flashes, then a 3-second pauseInsufficient water heating.
- Bradford White 4 flashes, then a 3-second pauseExcessive tank temperature. (3 meanings, by gas control)
- Bradford White 5 flashes, then a 3-second pauseTemperature sensor fault. (4 meanings, by gas control)
- Bradford White 6 flashes, then a 3-second pauseA water leak has been detected by an accessory module (some models only): an excessive amount of water in the drain pan or water dam. (2 meanings, by gas control)
- Bradford White 7 flashes, then a 3-second pauseA gas valve electronic fault has been detected.
- Bradford White 8 flashes, then a 3-second pauseA false pilot flame is present: the pilot valve is stuck in the open position.
- Bradford White 9 red flashes, then a 3-second pause (Ultra Low NOx)Tank leakage has been detected by an accessory module.
- Bradford White 10 red flashes, then a 3-second pause (Ultra Low NOx)An abnormal combustion chamber temperature profile was seen during the heating cycle.
Nothing matches all of those. Try “Any” on one choice, and count again: wait for the pause, then count the flashes before the next pause.
Only Rheem (blue for normal, red for faults) and Bradford White’s Resideo V2 control (green, yellow, red) name colours; a light whose maker names no colour matches any colour you pick.
By brand
- Rheem10 patterns
- A.O. Smith and State8 patterns
- Bradford White14 patterns
- LED off, not flashing
- 1 flash, then a pause of 3 to 4 seconds
- 1 flash every second
- 2 quick flashes (a strobe), then a pause
- LED on steady
- 2 flashes, then a 3-second pause
- 3 flashes, then a 3-second pause
- 4 flashes, then a 3-second pause
- 5 flashes, then a 3-second pause
- 6 flashes, then a 3-second pause
- 7 flashes, then a 3-second pause
- 8 flashes, then a 3-second pause
- 9 red flashes, then a 3-second pause (Ultra Low NOx)
- 10 red flashes, then a 3-second pause (Ultra Low NOx)
What these pages cannot do
- They cover only US gas tank water heaters with a status light on the gas control valve. A heater with a mechanical gas control (no light) has no code to read.
- They give no repair instructions of their own. Each page repeats only the steps the maker addresses to the owner — mostly relighting the pilot by the label’s instructions, and waiting — and names the repair the maker leaves to a qualified service technician so you know what to expect.
- They never tell you to reset or work around a safety device. Where a heater shuts down for overheating, flammable vapors or combustion air, the pages say what the maker says: call for service.
- They cannot tell two gas controls apart for you. Bradford White’s manual has three tables, and the same count means different things on each; its pages show all of them side by side. 3 of the patterns here are a light on steady, which on every brand means the knob was just turned off or the pilot just went out: wait for it to go dark before relighting.
Left out, and why
A brand gets pages when its own manual documents at least 5 status-light patterns and we could read them. Rheem, A.O. Smith (with State) and Bradford White did. These were not used:
- Ruud — Ruud is Rheem’s sister brand, but the Use & Care manual linked from Ruud’s own Professional Achiever atmospheric product page (AP22543 Rev 04, HTTP 200) has no status-light chart, so Rheem’s chart is not copied onto Ruud heaters. Check your Ruud manual for a status light before using the Rheem pages. www.ruud.com Checked 2026-09-29.
- Tankless gas water heaters (Rinnai, Navien, Noritz and others) — Tankless heaters show numbered error codes on a digital display, not a flashing status light on a tank’s gas valve. They belong in the error-codes family and are left for a later task there, not guessed here. Checked 2026-09-29.
- Resideo (Honeywell) and SIT as valve makers — Resideo and SIT make the gas controls, but the owner-facing tables are the ones each heater maker prints in its own manual for its own heater. Bradford White’s manual names the control maker in each table, and those tables are what the Bradford White pages use; no separate valve-maker pages were built. Checked 2026-09-29.
- Electric, heat-pump and power-vent models — Electric and heat-pump (hybrid) heaters and power-vent gas heaters use different controls with their own displays or codes. These pages cover only atmospheric gas tank heaters with a status light on the gas valve. Checked 2026-09-29.
Sources
Each maker’s own manuals and pages only, read on the date shown.
Rheem
- Rheem Manufacturing Company: Use & Care Manual with Installation Instructions — Water Heaters, Residential Gas, FVIR Certified (AP23060 Rev 01), “Combination Gas Control, Status Light Troubleshooting” — Rheem residential atmospheric gas water heaters, 29 to 60 gallons, natural or LP gas — the manual linked from the Rheem Performance atmospheric XG40T06EC36U1 product page. www.rheem.com Checked 2026-09-29.
- Rheem Manufacturing Company: Use & Care Manual with Installation Instructions — Water Heaters, Residential Gas, Low NOx Emissions (AP23698), “Gas control (Thermostat), Status Light Troubleshooting” — Rheem residential Low NOx (10 ng/J, SCAQMD Rule 1121) atmospheric gas water heaters, 29 to 55 gallons. files.myrheem.com Checked 2026-09-29.
A.O. Smith and State
- A.O. Smith: Residential Gas Water Heater Installation Instructions and Use & Care Guide (100263112, January 2015), “Status Light Code Troubleshooting Chart” and “Lighting the Pilot” — A.O. Smith residential atmospheric gas water heaters with the Flammable Vapor Ignition Resistant safety system and an electronic gas control valve. assets.hotwater.com Checked 2026-09-29.
- State Water Heaters (A.O. Smith): Residential Standard Gas Water Heater Service Handbook (327306), “Diagnostic Flash Codes” — State residential standard (atmospheric) gas water heaters with the electronic gas control valve/thermostat — a handbook written for qualified service professionals. www.statewaterheaters.com Checked 2026-09-29.
Bradford White
- Bradford White Corporation: Gas-Fired Water Heater Installation and Operation Manual (238-51007-00R, REV 07/26), “Troubleshooting — ICON System Electronic Gas Control” (Resideo V1, Resideo V2, SIT) — Bradford White residential gas-fired tank water heaters with the ICON System electronic gas control. docs.bradfordwhite.com Checked 2026-09-29.
- Bradford White Corporation: Ultra Low NOx Gas Water Heater Installation and Operation Manual (238-53393-00K, REV 08/26), “Troubleshooting — Resideo V1” and “Troubleshooting — Resideo V2” — Bradford White Ultra Low NOx residential gas tank water heaters with the ICON System electronic gas control. docs.bradfordwhite.com Checked 2026-09-29.
- Bradford White Corporation: FAQ: What does the flashing light(s) mean on my water heater’s gas valve? — Bradford White water heaters with the ICON gas valve system. www.bradfordwhite.com Checked 2026-09-29.