A.O. Smith Water Heater Error Code 031

Error code 031 means the control board has detected that the dipswitches on the computer board are not set to a valid or correct configuration. These small switches tell the board key information about the unit's setup, and any incorrect position will trigger this fault. The unit will not operate normally until the switch positions are corrected. This is typically a configuration issue rather than a component failure.

The unit is designed to stop normal operation when it detects an invalid dipswitch configuration, which is a protective measure to prevent running with incorrect settings. While the error itself is a configuration fault rather than a dangerous condition, you should not attempt to bypass it or force the unit to run without correcting the switch positions. Restore the correct configuration before returning the unit to service.

If the fix only requires adjusting the dipswitch positions, the repair cost is limited to a service call fee, which typically ranges from $75 to $150 depending on your location and the technician. If a damaged dipswitch or a faulty control board needs to be replaced, parts and labor costs can range from $150 to $400 or more. In many cases this is a straightforward configuration correction that does not require any replacement parts.

Turn off the power supply to the unit and remove the front cover to access the control board. Locate the left and right dipswitch banks on the board and compare each switch position against the correct settings for your specific model, which are usually listed on a label inside the unit. Adjust any switches that are in the wrong position, replace the cover, restore power, and check whether the error clears. If the switches are all correct and the error remains, a faulty board may be the cause.

A simple power reset will not permanently clear code 031 if the dipswitches remain in incorrect positions. The board checks the switch configuration on startup, so the error will return each time power is restored until the switches are set correctly. The underlying configuration must be corrected first for the reset to result in normal operation.