Description of Fault
A CATALYST Return Sensor Fault is issued when return temperature readings within the CATALYST system have abnormal readings either high (248° F) or low (–40° F). A reading of –40° F or 248° F indicates a wiring problem between the return sensor and the CATALYST controller.
A CATALYST Return Sensor Fault will automatically reset when the sensor reads an appropriate temperature.
The return temperature sensor is installed in the return duct of the unit and is wired with the CO2 sensor.
Possible Causes
A CATALYST Return Sensor Fault is typically caused by:
- An open wire (–40° F).
- A shorted wire (248° F).
Troubleshooting
From the eIQ Platform
- If the eIQ shows a return temperature of –40° F, this indicates an open wire between the return sensor and the CATALYST controller.
- If the eIQ shows a return temperature of 248° F, this indicates a shorted wire between the return sensor and the CATALYST controller.
- A technician will need to investigate in either scenario.
On Site
- Investigate the wiring at the sensor.
- Investigate the connection between the yellow 4C wire from the CATALYST controller into the return duct.