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E1

A.O. Smith Water Heater

Severity:

Source: OnlyErrorCodes.com — Every error code. One place.

A.O. Smith Water Heater E1 — Ignition Lockout

What Does This Error Mean?

E1 on an A.O. Smith water heater means the gas burner failed to ignite within the allowed attempts and the unit locked out. Verify the gas supply is on and the vent is clear, then reset the unit.

Affected Models

  • A.O. Smith Signature
  • A.O. Smith Signature 100
  • A.O. Smith ProLine
  • A.O. Smith GPVH Gas Series

Common Causes

  • Gas supply valve closed or inlet pressure too low
  • Empty or low propane tank on LP models
  • Dirty igniter unable to spark reliably
  • Blocked intake or exhaust vent
  • Flame sensor coated in oxide deposits

How to Fix It

  1. Verify the gas supply.

    Check that the manual shutoff valve behind the water heater is fully open (handle parallel to the pipe). Test another gas appliance — if the stove has no gas, the problem is upstream at the meter.

  2. Check the vent pipes.

    Inspect both intake and exhaust vent terminals outside the building for debris, ice, or bird nests. Blocked vents prevent combustion and trigger E1.

  3. Reset the unit.

    On most A.O. Smith models, set the thermostat to its lowest position for 30 seconds, then turn back up. Some models have a dedicated red reset button on the thermostat panel — press it firmly.

  4. Listen during restart.

    After resetting, listen for the igniter clicking, then the burner lighting. Repeated clicking with no ignition points to an igniter or gas supply issue.

When to Call a Professional

If E1 persists after verifying gas supply and vents, a licensed plumber should inspect the igniter, flame sensor, and gas valve.

Frequently Asked Questions

How do I reset E1 on an A.O. Smith water heater?

Turn the thermostat dial to its lowest setting, wait 30 seconds, then turn back up. If there is a red or white reset button on the thermostat panel, press it firmly. The unit will then attempt ignition.

Why does A.O. Smith E1 keep coming back after I reset?

Repeating E1 means the root cause has not been resolved. The most common persistent causes are a faulty igniter, blocked vent, or low gas pressure. A technician should test these components.