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A. O. Smith 0 flashes

A. O. Smith status light off (0 flashes): pilot out

By USA Expert Plumbing Editorial Team. Updated . 2 min read.

Short answer

When the status light on an A. O. Smith gas valve is off, the pilot is not lit or the thermopile has not reached operating temperature yet. A. O. Smith says to turn the knob to OFF, wait 10 minutes and relight the pilot. The light can take up to 90 seconds of steady pilot to start blinking.

In this guide
  1. What to do
  2. If the pilot will not light or stay lit
  3. Before you call

The status light on this A. O. Smith gas control is powered by the pilot flame through a thermopile. No pilot, or a pilot that has not heated the thermopile yet, means no light at all.

The meaning below comes from the status light chart in A. O. Smith's installation and use manual for its residential gas water heaters with a pilot-powered gas control valve. The same control is used on State and other A. O. Smith-made heaters.

Four A. O. Smith status light states: light off, solid red, one flash every three seconds and two flashes
The status light only works once the pilot has heated the thermopile, which can take up to 90 seconds.

What to do

  1. Turn the gas control knob to OFF and wait 10 minutes. A. O. Smith's control requires this wait between lighting attempts.
  2. Relight the pilot following the instructions on the heater's label.
  3. Keep the pilot running. The status light may take up to 90 seconds to start blinking.
  4. If it still does not blink after three attempts, make sure the heater is getting gas.

If the pilot will not light or stay lit

  • A. O. Smith says to remove the outer door, press the reset button, replace the door and try again after 10 minutes.
  • If no pilot flame is visible through the view port, the spark igniter or the gas supply to the pilot needs checking.
  • If the pilot is visible but the light does not blink after 90 seconds, the pilot may be too weak to heat the thermopile, the thermopile may be defective or a wire may be loose.

If the heater stopped on its own and will not relight, A. O. Smith says to check the flame arrestor for blue or black heat discoloration. That can indicate a flammable vapor incident, and the heater should not be used until a technician inspects it.

If you smell gas, do not reset the unit or touch any switches. Leave the building and call your gas utility from outside.

Before you call

Note the exact flash pattern, count it twice, and have the model and serial number from the rating label ready. Tell the technician when the light started flashing, whether the pilot is lit, and whether anything was stored or spilled near the heater recently. The serial number also tells you the heater's age, which matters when deciding between a repair and a replacement.

See every code on our A. O. Smith status light codes page.

Common questions

How long does it take for the A. O. Smith status light to blink?

Up to about 90 seconds of continuous pilot operation, while the thermopile warms up.

Why does A. O. Smith say to wait 10 minutes between attempts?

The gas control has built-in circuitry that requires the wait, and it also lets gas clear before relighting.

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Other A. O. Smith codes

CodeMeaning
0 flashes Light off: pilot out or thermopile not yet warm
Solid red Solid red light: pilot recently went out, thermopile cooling
2 flashes Pilot lit but thermopile output too low
4 flashes Water temperature too high (high limit tripped)
5 flashes Temperature sensor (thermistor) failure
7 flashes Gas control valve failure
8 flashes Thermopile still producing power with the knob off (pilot valve may be stuck open)

All A. O. Smith error codes