Rheem Water Heater Error Code 13

Error code 13 on a Rheem water heater indicates a persistent fault condition that remains active even after the standard reset procedure has been performed for error code 12. Error code 12 is associated with a flame failure or ignition fault, meaning the burner either failed to ignite or the flame was not detected by the flame sensor during a heating cycle. When the control board logs this failure repeatedly and the standard reset does not clear the underlying issue, the unit escalates to error code 13 to signal that the problem requires professional attention rather than further DIY intervention.

The components most likely involved include the igniter assembly, flame sensor rod, gas valve, and the main control board. A flame sensor that is fouled, corroded, or out of position will fail to detect a valid flame signal and cause repeated ignition faults. Similarly, a weak or failed igniter will prevent the burner from lighting consistently. Gas supply issues such as low inlet pressure or a partially closed shutoff valve can also cause repeated flame failures that compound into this persistent fault state.

Because error code 13 specifically signals that standard reset steps have already been exhausted without resolving the root cause, further troubleshooting requires diagnostic tools and technical expertise. Attempting additional resets without addressing the underlying component failure is unlikely to resolve the issue and may result in unsafe operating conditions. Rheem recommends contacting a licensed dealer or qualified service technician for diagnosis and repair at this stage.