A. O. Smith gas water heaters signal faults by category, such as ignition, flame loss, or venting, rather than a single universal code list.
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Quick answer
A. O. Smith gas water heaters with electronic controls typically indicate faults through a flashing status light or digital code that falls into a handful of general categories: ignition failure, flame loss during operation, venting or exhaust restriction, water flow or sensor faults, and over-temperature shutdowns. The exact flash pattern or digital code varies by model and control board generation, so always verify against the manual or rating plate for your specific unit rather than relying on a generic list.
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A. O. Smith has used several different control platforms across its residential gas water heater lines over the years, and the exact numeric or flash-count code for the same underlying fault can differ between a standard atmospheric-vent tank, a power-vent tank, and different generations of electronic gas control valves. Rather than publish a numbered list that may not match your specific model and could lead to a wrong assumption, this guide describes the general fault categories your unit is likely reporting and what a licensed technician checks for each. Always confirm the exact meaning of a flash pattern or digital readout against the owner's manual for your specific model, which usually includes a code chart on the inside of the front access panel or in the printed documentation.
| Category | Typical Symptom | What It Usually Means |
|---|---|---|
| Ignition failure | Unit will not light, repeated clicking | Igniter, gas valve, or gas supply issue preventing initial flame establishment |
| Flame loss / flame sense fault | Lights briefly then shuts down | Flame sensor not detecting a stable flame after ignition |
| Venting / exhaust fault | Shutdown especially on power-vent models | Blocked, disconnected, or improperly sloped venting, or a failed vent motor/pressure switch |
| Over-temperature / high-limit trip | Unit shuts off and needs manual reset | Safety control detecting water or flue temperature above the allowed limit |
| Flow or sensor fault | Inconsistent heating, code on some tankless-style controls | A temperature or flow sensor reporting an out-of-range signal |
CANRO frequently traces venting-related fault codes in Metro Vancouver to two things: bird or debris intrusion in exterior vent terminations, which is more common near the coast and in leafy neighbourhoods, and condensation or corrosion inside older metal venting exposed to the region's damp climate over many years. Power-vent models add a blower and pressure switch to the mix, and either component failing, or the switch simply detecting restricted airflow, can trigger a venting-category code even when the tank's gas components are otherwise fine.
Because a venting fault directly affects how combustion byproducts are removed from the home, never bypass or disable a fault code related to venting. Have it inspected before continuing to use the appliance.
A single ignition or flame-sense fault on a tank under roughly eight years old is usually a straightforward part repair. Repeated venting faults on an older atmospheric-vent installation, or a control board failure on a tank already showing tank-side corrosion, are better discussed as a possible replacement, since combining a major control repair with an aging tank often is not the most cost-effective path. A. O. Smith's documented service life expectations are a general guide only; actual lifespan depends on water quality, venting condition, and maintenance history.
Safety note
Never disable, bypass, or repeatedly override a safety shutdown code, especially one related to venting, flame sensing, or over-temperature. If you notice a burning smell, soot, or a gas odour along with an error code, leave the home and call FortisBC at 1-800-663-9911 from outside immediately. Gas control valve, venting, and burner work must be performed by a Technical Safety BC licensed gas fitter. CANRO holds gas licence LGA0043870.
A. O. Smith has used multiple control platforms over the years, and the same fault can produce a different flash pattern or digital code depending on model and control board generation, so we describe the fault categories and recommend verifying the exact code against your unit's manual.
Check inside the front access panel for a code chart sticker, or look up the model number, usually on a rating plate on the tank, to find the matching manual online; a licensed technician can also identify the fault on site.
A couple of reset attempts following the manual's instructions is generally fine, but repeatedly resetting a persistent fault, especially a venting or flame-sense code, can mask a real safety issue and should be avoided.
Yes, CANRO sees venting-related faults fairly often here, frequently linked to debris in exterior vent terminations or corrosion in older metal venting exposed to coastal dampness.
No, most single-component faults like an ignition or flame-sense issue are repairable. Replacement becomes the more sensible option when a major control fails on an already aging tank.
Manufacturer documentation for your specific model and control board generation is the most reliable source; verify against the manual for your model rather than a generic list found elsewhere.
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