Technician Taylor arrived on scene to investigate reports of water heater showing error code. Technician found client had unplugged water heater and plugged in outlet splitter to supply power to another accessory. Once you turned everything back on the error code e438 showed up. Afterwards she reset the unit and the code had since gone away. technician got on the phone with Nathan tankless support and registered clients unit. Technician drain down filter and tested valve. Technician reset unit and no error codes were showing. Technician cleaned work area and pulled off