Trane VUV Installation, Operation And Maintenance Manual page 111

Table 60. Diagnostics generated by UC400-B/Symbio™ 400-B controller
Diagnostic Probable Cause
Fan run hours exceed the time set to indicate
Filter change required
filter change.
Condensate overflow The drain pan is full of water.
The leaving fluid temperature may be close to
Low coil temp detection
freezing.
The fan drive belt, contactor, or motor has
Low airflow supply fan failure
failed.
(a)
Space temperature failure Invalid or missing value for zone temperature.
Entering water temp failure Invalid or missing value for zone temperature.
Discharge air temperature has fallen below the
Discharge air temp low limit
Discharge Air Temperature Low Limit.
Invalid or missing value for discharge air
Discharge air temp failure(a)
temperature.
Invalid or missing value for outdoor air
Outdoor air temp failure
temperature.
Humidity input failure Invalid or missing value for relative humidity.
CO sensor failure Invalid or missing value for CO
2
Invalid or missing value for generic analog
Generic AIP failure
input.
Invalid or missing fan-speed switch (reverts to
Local fan mode failure
default fan speed).
Invalid or missing value for zone temperature
Local setpoint failure
setpoint (reverts to default setpoint).
(a) For detailed information about zone temperature control methods, refer to
UV-SVX005G-EN
Consequences
• Fan Unaffected
• Valves Unaffected
• Electric heat Unaffected
• Fan OFF
• Valves Closed
• 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
• Valved 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
.
2
• Outdoor air damper Unaffected
• 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
• Fan Unaffected
• Valves Unaffected
• Outdoor air damper Unaffected
• DX cooling/electric heat Unaffected
"Zone Temperature Control," p. 84
Diagnostics and Troubleshooting
Diagnostic Type
Informational
Manual
Smart reset/Manual
Manual
Automatic
Automatic
Smart reset/manual
Automatic
Automatic
Automatic
Informational
Informational
Automatic
Automatic
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