Tracer UC 400 Controller
UNT-SVX07E-EN
145
Manual (Latching) Diagnostics
Manual diagnostics (also referred to as latching) cause the
unit to shut down. Manual diagnostics can be cleared from
the UC400 controller in one of the following ways:
•
By using the Tracer TU service tool to reset latching
diagnostics on the
Alarms Status
tab or by
temporarily overriding the
Reset Diagnostic
Request
(bv/2) on the
Binary Status
tab.
•
Through a building automation system.
•
By cycling power to the controller. When the 24Vac
power to the controller is cycled
OFF
and then
ON
again, a power-up sequence occurs.
Automatic (Non-latching) Diagnostics
Automatic diagnostics clear automatically when the
problem that generated the diagnostic is solved.
Smart Reset Diagnostics
Smart Reset Diagnostics are latching diagnostics that will
auto-recover if the condition is corrected. After the
controller detects the first smart reset diagnostic, the unit
waits 30 minutes before initiating the smart reset function.
If another diagnostic of this type occurs again within
24 hours after an automatic clearing, clear the diagnostic
manually by using any of the ways listed under the
preceding section,
“Manual (Latching) Diagnostics.”
Informational Diagnostics
Informational diagnostics provide information about the
status of the controller. They do not affect machine
operation, but can be cleared from the controller using the
BAS or Tracer SC.
Building Automation System
Some building automation systems can reset diagnostics
in the controller. For more complete information, refer to
the product literature for the building automation system.
Trane Service Tools
Tracer TU can be used to reset diagnostics present in a
Tracer UC400 controller.
Controller Diagnostics
Table 87
lists each diagnostic that can be generated by the
UC400 controller, the diagnostic effect on outputs
(consequences), and diagnostic type.
Note:
The generic binary output is unaffected by
diagnostics.
Table 87.
Diagnostics generated by UC4000 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
• Valves
Closed
• 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
1
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
1
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
• Valved
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 CO
2
.
• Fan
Unaffected
• Valves
Unaffected
• Outdoor air damper
Unaffected
• DX cooling/electric heat
Unaffected
Informational
