A.O. Smith gas water heater status light: 8 flashes, then a pause
This 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.
If you smell gas
Stop: do not relight or troubleshoot anything. A.O. Smith’s own words (Residential Gas Water Heater Installation Instructions and Use & Care Guide 100263112, cover page):
- Do not try to light any appliance.
- Do not touch any electrical switch; do not use any phone in your building.
- Immediately call your gas supplier from a neighbor’s phone. Follow the gas supplier’s instructions.
- If you cannot reach your gas supplier, call the fire department.
Calling from a neighbor’s phone means leaving the building first.
What you see: 8 flashes, then a pause, repeating. Applies to: A.O. Smith residential atmospheric gas water heaters with the Flammable Vapor Ignition Resistant safety system and an electronic gas control valve. State heaters use the same codes.
What it means
The manual’s wording: “8 FLASHES” — A.O. Smith and State electronic gas control valve.
This 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.
What A.O. Smith tells the owner to do
- A.O. Smith says to make sure the gas control knob is set to OFF, wait one minute, and look through the sight glass for a pilot flame.
- A.O. Smith says that if a pilot flame is burning with the knob at OFF, the pilot valve is stuck open: turn the main gas supply OFF.
- A.O. Smith says that if there is no pilot flame with the knob at OFF, wait 10 minutes for the thermopile to cool, then relight the pilot following the lighting instructions on the water heater’s label.
semiatic gives no repair instructions of its own. The steps above are only the ones A.O. Smith addresses to the owner in its manual.
The repair A.O. Smith’s table gives — for the qualified person you call
Shown so you know what to expect, not as steps to do yourself: A.O. Smith reserves repairs to the gas control, burner and gas piping for a qualified service technician.
- replace the gas control valve/thermostat if the pilot valve is stuck open, or if the condition returns after relighting.
When to call a qualified service agency
A.O. Smith’s manual: “Installation and service must be performed by a qualified installer, service agency or the gas supplier.” Its Technical Assistance Hotline is 1-800-527-1953; have the model and serial number from the data plate ready.
Source
A.O. Smith’s own manuals, read on the date shown.
- 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.
The same pattern on other brands
The same count on another maker’s gas control can mean something else.