Trane BCHE - Diagnostics and Troubleshooting; Diagnostics generated by UC400-B controller

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