What actions are recommended if my Ruud Ultra Plug-in Heat Pump with HydroBoost (120V Shared Circuit) displays Alarm Code A104?
CAUTION: For your safety, DO NOT attempt repair of electrical wiring, controls, heating elements, or other safety devices. Refer repairs to qualified service personnel.
Possible Cause: Lower tank temperature sensor malfunction, resulting in the heater being disabled. What To Do:
- Thoroughly inspect and ensure the connections of the wiring and sensors are intact and secure.
- If you have a multimeter on hand, determine the Ohm reading on the thermistors. It’s important to use the Ohm chart for accurate readings in relation to the current ambient temperature.
- On the device’s interface, navigate to Service –> Sensors. A -40°F reading indicates that the circuit is open, while a +250°F reading suggests a shorted circuit. To further confirm this, deactivate the unit, disconnect the thermistor from its board, and re-evaluate the Ohm reading.
This answer is applicable for the following model: Ruud Ultra Plug-in Heat Pump with HydroBoost (120V Shared Circuit).