Installation and Maintenance Manual

Diagnostics
UNT-SVX07D-EN 11 5
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 T
racer TU analog or
multistate 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: Cleari
ng diagnostics refers to deleting diagnostics
from the software; it does not affect the problem
that generated the message.
Table 43. Fresh air damper stays closed (Tracer ZN520)
Probable
Cause Explanation
Normal
operation
The controller opens and closes the fresh air damper based
on the controller’s occupancy mode and fan status.
Normally, the fresh air damper is open during occupied mode
when the fan is running and closed during unoccupied mode.
Warmup and
cooldown
The controller includes both a warmup and cooldown
sequence to keep the fresh air damper closed during the
transition from unoccupied to occupied. This is an attempt to
bring the space under control as quickly as possible.
Requested
mode: off
It is possible to communicate the operating mode (such as
off, heat, cool) to the controller. When off is communicated
to the controller, the unit closes the fresh air damper.
Manual output
test
The controller includes a manual output test sequence that
verifies analog and binary output operation and associated
output wiring. However, based on the current step in the test
sequence, the fresh air damper may not be open. Refer to
“Manual Output Test (Tracer ZN520),” p. 113.
Diagnostic
present
A specific list of diagnostics effects fresh air damper
operation. For more information, see “Diagnostics,” p. 112.
Unit
configuration
The controller must be properly configured based on the
actual installed end devices and application. When the unit
configuration does not match the actual end device, the
damper may not work correctly.
No power to
the controller
If the controller does not have power, the fresh air damper
does not operate. For the controller to operate normally, a
24 Vac input voltage must be applied. When the green LED
is off continuously, the controller does not have sufficient
power or has failed.
Unit wiring The wiring between the controller outputs and the fresh air
damper must be present and correct for normal damper
operation. Refer to the typical unit wiring diagrams (see
“Wiring Diagrams,” p. 133).
UNT-SVX07_-EN.book Page 115 Friday, April 27, 2012 9:40 AM