Rinnai - Troubleshooting Tankless Water Heater Error Codes: Rinnai

While their products can be costly, their reliability is also good.

However, the basics of changing the temperatures on all water heaters are pretty much the same.

Error Code 03: Power interruption during Bath fill Rinnai error code 03 indicates that there has been a power interruption or outage while the Rinnai water heater happens when in use.

If there is a dedicated return line in the house, a recirculation pump will move the water from the heater through the return line and back.