A. O. Smith water heater codes
A gas tank water heater reports its fault as a count of LED flashes on the gas control valve, seen through the small window or viewport near the base of the tank. Count the flashes, note the pause (usually three seconds) and watch a second full round before you decide which code it is. Some controls use two groups, such as six flashes then one.
All 6 codes
About A. O. Smith codes
A. O. Smith makes tank water heaters whose gas control valve has a status light that flashes a fault code, then pauses three seconds and repeats. The meaning depends on the control, so match the chart to your model series. Check the model label on your unit before using any chart.