Warning: Disconnect power before servicing.

A.O. Smith Waterheater Error Codes

All A.O. Smith waterheater error codes with step-by-step troubleshooting, multimeter specs, and OEM part numbers.

1 error codes

CodeMeaning
NO-HEATSomething broke the heating circuit. On electric units, power either isn't reaching the elements or the elements themselves are toast. Gas units usually mean the pilot's out, the thermocouple gave up, or the gas valve stopped doing its job. Either way, no heat transfer is happening inside that tank.
highintermediate