What does error code 2 flashes mean on a A.O. Smith water heater?

Thermopile voltage low. The thermopile voltage is low.

Can I fix A.O. Smith code 2 flashes myself?

Start with these safe checks: Note the code. Checking wiring and thermopile millivolts are service steps. A qualified technician checks connections and replaces the thermopile if it reads under 350 mV.

When should I call a technician for code 2 flashes?

A qualified technician checks connections and replaces the thermopile if it reads under 350 mV. Smell gas? Leave right away, don't touch light switches or phones inside, and call your gas utility or 911 from outside. Never open a gas valve, burner, gas line, vent or flue connection, or bypass a safety switch. Repeated lockouts, scorching, soot, or a CO alarm mean shut it off and call a licensed gas technician.

A.O. Smith Water Heater Error Code 2 flashes: Thermopile voltage low

What 2 flashes means

The thermopile voltage is low.

Likely causes

Weak thermopile
Loose wiring
Small or dirty pilot flame

Safe first checks

Note the code. Checking wiring and thermopile millivolts are service steps.

When to stop

A qualified technician checks connections and replaces the thermopile if it reads under 350 mV.

Checked against: A.O. Smith Residential Standard Gas Water Heater Service Handbook: diagnostic flash codes. Codes can differ by model and year, so confirm with your owner's manual.