Error A104 means the upper tank temperature sensor malfunctioned. Therefore, the heater was disabled. The following steps can help you check the issue.
- Check connections of the wiring and sensors.
- Get an Ohm reading on the thermistors (if multimeter is available) (See Ohm chart for correct readings based on ambient temperature).
- Check on display by selecting Service>Sensors>If sensor shows – 40°F, the circuit is open, +250°F indicates the circuit has shorted. Note: To confirm reading, power down the unit and unplug the thermistor from the board. Check Ohm reading. (See ohms chart)
Zwell is dedicated to getting homes closer to net zero through the installation of new energy-efficient hybrid water heaters. We are not currently equipped to do service or repair visits but we want to be as helpful as possible. Feel free to reach out to us here or for more information, you can contact the Rheem Hybrid Technical Services Department at 800-995-0982.