Installation and Maintenance Manual

Diagnostics
102 UV-SVN02C-EN
Unit
configuration
The controller must be properly configured based on the
actual installed end devices and application. If the unit
configuration does not match the actual end device, the
valves may not work correctly.
Random start
observed
After power-up, the controller always observes a random
start from 5 to 30 seconds. The controller remains OFF
until the random start time expires.
Requested
mode off
The user can communicate a desired operating mode (such
as OFF, heat, and cool) to the controller. If OFF is
communicated to the controller, the unit controls the fan to
off. There is no heating or cooling.
Entering water
temperature
sampling logic
The controller includes entering water temperature
sampling logic, which is automatically initiated during
2-pipe and 4-pipe changeover, if the entering water
temperature is either too cool or too hot for the desired
heating or cooling.
Valve
configuration
Ensure the valves are correctly configured, using the Tracer
TU service tool, as normally open or normally closed as
dictated by the application.
Table 50. Valves remain open (UC400)
Probable
Cause Explanation
Unit wiring The wiring between the controller outputs and the valve(s)
must be present and correct for normal valve operation.
Refer to applicable wiring diagram.
Failed end
device
The valves must be checked to ensure proper operations.
Normal
operation
The controller opens and closes the valves to meet the unit
capacity requirements.
Diagnostic
present
Several diagnostics affect valve operation. For detailed
information about these diagnostics, refer to Table 37,
p. 93.
Unit
configuration
The controller must be properly configured based on the
actual installed end devices and application. If the unit
configuration does not match the actual end device, the
valves may not work correctly.
Entering water
temperature
sampling logic
The controller includes entering water temperature
sampling logic, which is automatically initiated during 2-
pipe and 4-pipe changeover, if the entering water
temperature is either too cool or too hot for the desired
heating or cooling.
Valve
configuration
Ensure the valves are correctly configured, using the Tracer
TU service tool, as normally open (NO) or normally closed
(NC) as dictated by the application.
Freeze
avoidance
When the fan is OFF with no demand for capacity (0%),
and the outdoor air temperature is below the freeze
avoidance setpoint, the controller opens the water valves
(100%) to prevent coil freezing. This includes unoccupied
mode when there is no call for capacity or any other time
the fan is OFF.
Table 49. Valves remain closed (UC400) (continued)
Probable
Cause Explanation
Table 51. DX or electric heat does not energize (UC400)
Probable
Cause Explanation
Unit wiring The wiring between the controller outputs and the end
devices must be present and correct for normal operation.
Refer to applicable wiring diagram.
Failed end
device
Check the control contactors or the electric heat element,
including any auxiliary safety interlocks, to ensure proper
operation.
No power to
the controller
If the controller does not have power, heat outputs do not
operate. For the controller to operate normally, apply an
input voltage of 24 Vac. If the Marquee/Power LED is OFF
continuously, the controller does not have sufficient power
or has failed.
Diagnostic
present
Several diagnostics affect DX and electric heat operation.
For detailed information about these diagnostics, refer to
Table 37, p. 93.
Normal
operation
The controller controls compressor or electric heat outputs
as needed to meet the unit capacity requirements.
Unit
configuration
The controller must be properly configured based on the
actual installed end devices and application. If the unit
configuration does not match the actual end device, DX or
electric heat may not operate correctly.
Requested
mode off
The user can communicate a desired operating mode (such
as OFF, heat, and cool) to the controller. If OFF is
communicated to the controller, the unit shuts off the
compressor or electric heat.
Freeze
avoidance
When the fan is OFF with no demand for capacity (0%),
and the outdoor air temperature is below the freeze
avoidance setpoint, the controller disables compressors
and electric heat outputs (100%) to prevent coil freezing.
This includes unoccupied mode when there is no call for
capacity or any other time the fan is OFF.
Table 52. Outdoor air damper remains closed (UC400)
Probable
Cause Explanation
Unit wiring The wiring between the controller outputs and the outdoor
air damper must be present and correct for normal outdoor
air damper operation. Refer to applicable wiring diagram.
Failed end
device
Check damper actuator to ensure proper operation.
No power to
the controller
If the controller does not have power, the outdoor air
damper does not operate. For the controller to operate
normally, apply an input voltage of 24 Vac. If the Marquee/
Power LED is OFF continuously, the controller does not
have sufficient power or has failed.
Diagnostic
present
Several diagnostics affect outdoor air damper operation.
For detailed information about these diagnostics, refer to
Table 37, p. 93.
Normal
operation
The controller opens and closes the outdoor air damper
based on the controller’s occupancy mode and fan status.
Normally, the outdoor air damper is open during occupied
mode when the fan is running and closed during
unoccupied mode.
Unit
configuration
The controller must be properly configured based on the
actual installed end devices and application. If the unit
configuration does not match the actual end device, the
outdoor air damper may not work correctly.
Warm-up and
cool-down
sequence
The controller includes both a morning warm-up and cool-
down sequence to keep the outdoor 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
The user can communicate a desired operating mode (such
as OFF, heat, or cool) to the controller. If OFF is
communicated to the controller, the unit closes the outdoor
air damper.
UV-SVN02_-EN.book Page 102 Thursday, January 24, 2013 4:48 PM