Installation and Maintenance Manual

Diagnostics
UV-SVN02C-EN 93
Output Testing and Diagnostics
(UC400)
This section provides information about the following:
• Output testing
• Diagnostics
Note: For detailed description of LED activities and
troubleshooting tips, refer to the section.
Output Testing (UC400)
Important: Do not directly overwrite the outputs.
Output testing can be accomplished by
overriding the following analog and
multistate value points in the desired state
or position:
• Cool valve request
• DX cool request
• Economizer request
• Electric heat request
• Heat valve request
• Supply fan speed request
The points can be overridden on the Tracer TU analog or
mu
ltistate pages by clicking on the Override icon in
the control column. A higher priority (lower number) must
be chosen over the current control setting.
Diagnostics (UC400)
Diagnostics are informational messages that indicate the
operational status of the UC400 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 (UC400)
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: Cle
aring diagnostics refers to deleting diagnostics
from the software; it does not affect the problem
that generated the message.
Manual (Latching) Diagnostics (UC400). 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 cont
roller. When the 24Vac
power to the controller is cycled OFF and then ON
again, a power-up sequence occurs.
Automatic (Non-latching) Diagnostics (UC400).
Automatic diagnostics clear automatically when the
problem that generated the diagnostic is solved.
Smart Reset Diagnostics (UC400). 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 (UC400).”
Informational Diagnostics (UC400). 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.
Table of Diagnostics (UC400)
Table 37 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 37. UC4000 diagnostics
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
UV-SVN02_-EN.book Page 93 Thursday, January 24, 2013 4:48 PM