Trane BCHE Installation, Operation And Maintenance Manual page 134

Diagnostics and Troubleshooting
Table 54. Diagnostics generated by UC400-B controller
Diagnostic Probable Cause
Filter change Fan run hours exceed the
required time set to indicate filter
change.
Condensate overflow The drain pan is full of
water.
Low coil temp The leaving fluid
detection temperature may be close
to freezing.
Low airflow supply The fan drive belt,
fan failure contactor, or motor has
failed.
Space temperature Invalid or missing value
failure (a) for zone temperature.
Entering water temp Invalid or missing value
failure for zone temperature.
Discharge air temp Discharge air temperature
low limit has fallen below the
Discharge Air
Temperature Low Limit.
Discharge air temp Invalid or missing value
failure for discharge air
temperature.
Outdoor air temp Invalid or missing value
failure for outdoor air
temperature.
Humidity input failure Invalid or missing value
for relative humidity.
CO sensor failure Invalid or missing value
2
for CO2.
134
Consequences
• Fan Unaffected
• Valves Unaffected
• Electric heat Unaffected
• Fan OFF
• ValvesClosed
• Outdoor air damper Closed
• DX/electric heat OFF
• Fan OFF
• Valves Open
• Outdoor air damper Closed
• DX/electric heat OFF
• Fan OFF
• Valves Closed
• Outdoor air damper Closed
• DX/electric heat OFF
• Discharge air temperature control runs
• Unit shuts OFF if both space temperature and discharge air
temperature fail
• Fan Unaffected (enabled)
• Valves Unaffected
• Outdoor air damper Unaffected
• DX/electric heat Unaffected
• Fan OFF
• Valves Open
• Outdoor air damper Closed
• DX/electric heat OFF
• Simplified zone control algorithm runs
• Unit shuts OFF if zone temperature fails
• Fan Unaffected
• Valve Unaffected
• Outdoor air damper Minimum Position
• DX cooling/electric heat unaffected
• Fan Unaffected
• Valves Unaffected
• Outdoor air damper Unaffected
• DX cooling/electric heat Unaffected
• Fan Unaffected
• Valves Unaffected
• Outdoor air damper Unaffected
• DX cooling/electric heat Unaffected
Diagnostic Type
Informational
Manual
Smart reset/Manual
Manual
Automatic
Automatic
Smart reset/manual
Automatic
Automatic
Automatic
Informational
BCX-SVX002A-EN