A051_A:
RDS Communication Failure
Status
This is a critical fault and system will not operate.
Description
The system has learned of the presence of a refrigerant detection sensor, and it is no longer visible on the communications bus.
This can happen when someone physically attempts to remove a A2L sensor for whatever reason from a system, or there is a wiring issue, or a sensor has failed completely, In some cases, the application has a "Cubic" branded sensor installed on a communicating system with an EcoNet thermostat that is connected to Wi-Fi.
1. Once a sensor is learned on the system, it cannot be removed to avoid alarms.
2. There is an error of problem with wiring the sensor between E1 of the communicating bus to terminal 2 on the sensor, or from E2 on the communicating bus to terminal 1 of the sensor. Yes, that is correct, E1 goes to pin 2 on the sensor, and E2 goes to pin 1 on the sensor.
3. The sensor has failed completely.
4. The air handler or cased coil is connected to an EcoNet thermostat which is connected to Wi-Fi AND has a "Cubic" branded sensor installed. A "cubic" branded sensor has the 5 open bars on the face resembling a "Jeep Grill". The "Sensirion" branded sensor has more of a circle cut out on the face. Often times this alarm would occur shortly after the homeowner provisions his Wi-Fi.
Solution
1. Reinstall the sensor per the manufactures instructions. an A2L system is required in almost all cases to have a sensor installed in the coil.
2. Verify wiring has not become disconnected, or is not mis-wired somehow. Correct wiring issue.
3. Replace sensor.
4. To correct the issue, disconnect the thermostat from Wi-Fi by pressing the Wi-Fi icon on the thermostat but do not complete the process to reconnect. Cycle the power to the air handler leaving it off for 3 minutes before restoring power. The thermostat may at some point reconnect using previous credentials so this is not a permanent solution. Verify the sensor is on a system with an EcoNet thermostat, and is expected to be connected to Wi-Fi. Verify the sensor installed is a "Cubic' branded sensor. If it is (the one with the "Jeep style grill"), replace the sensor with the "Sensirion" branded sensor. Part number for the Sensirion Refrigerant Detection Sensor is 47-109642-01.
