Diagnostics and Troubleshooting
80
UNT-SVX041D-EN
Overriding Outputs
Analog and multistate value request points are included in
order to safely override outputs without disrupting TGP2
program operation. To override valves and dampers for
commissioning or testing purposes, access the following
points on the Tracer
®
TU analog or multistate status
pages:
•
Cool valve request
•
Heat valve request
•
Electric heat request
•
Supply fan speed active
For more information, refer to:
BAS-SVX20*-EN Tracer®
UC400-B Programmable Controller Installation,
Operation, and Maintenance.
Diagnostics
Diagnostics are informational messages that indicate the
operational status of the controller. In response to most
diagnostics, the controller attempts to protect the
equipment by enabling/disabling, or by opening/closing
specific outputs. Other diagnostics provide information
about the status of the controller, but have no effect on
outputs. Diagnostics are reported in the order in which
they occur. Multiple diagnostics can be present
simultaneously. Diagnostic messages are viewed using
the Tracer® TU service tool or through a BAS.
Note:
Tracer® TU will report only active diagnostics.
Diagnostics Types
Diagnostics are categorized according to the type of
clearing method each uses and the type of information
each provides.
The diagnostic types are:
•
Manual (latching) diagnostics
•
Automatic (non-latching) diagnostics
•
Smart reset diagnostics
•
Informational diagnostics
Note:
Clearing diagnostics refers to deleting diagnostics
from the software; it does not affect the problem
that generated the message.
Manual (Latching) Diagnostics
Manual diagnostics (also referred to as latching) cause the
unit to shut down. Manual diagnostics can be cleared from
the UC400-B 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-B controller.
Controller Diagnostics
The table below lists each diagnostic that can be generated
by the UC400-B controller, the diagnostic effect on outputs
(consequences)
, and diagnostic type.
Note:
The generic binary output is unaffected by
diagnostics.
