A.O. Smith gas water heater status light: 4 flashes, then a pause
High water temperature has activated the overheat sensor (State’s handbook calls it “temperature exceeded (ECO activated)”). The heater shuts down.
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: 4 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: “4 FLASHES” — A.O. Smith and State electronic gas control valve.
High water temperature has activated the overheat sensor (State’s handbook calls it “temperature exceeded (ECO activated)”). The heater shuts down.
What A.O. Smith tells the owner to do
A.O. Smith’s manual gives the owner no step of their own for this code: call for service.
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.
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.