Troubleshooting
CNT-SVX05B-EN 97
Table 68. Outdoor air damper stays closed
Probable cause Explanation
Normal operation The controller opens and closes the outdoor air damper based on the controller's
occupancy mode and fan operation. Normally, the outdoor air damper is open during
occupied, occupied standby, and occupied bypass mode when the fan is running and
closed during unoccupied mode unless the controller is economizing. Refer to “Out-
door air damper operation” on page 56 for more information.
Warm-up and cool down 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
sequence is an attempt to bring the space under control as quickly as possible.
Unoccupied mode When the controller is in the unoccupied mode, the outdoor air damper remains
closed unless economizing is enabled.
Low ambient damper lock
out
When the outdoor air temperature is less than the low ambient damper lockout set-
point (which can be changed with the Rover service tool), the outdoor air damper is
closed.
Requested mode Off You can communicate a desired operating mode (such as Off, Heat, and Cool) to the
controller. When Off is communicated to the controller, the unit controls the fan Off.
There is no heating or cooling (valves are closed). The outdoor air damper is closed.
Power-up control wait When power-up control wait is enabled (non-zero time), the controller remains Off
until one of two conditions occurs:
The controller exits power-up control wait when it receives communicated
information.
The controller exits power-up control wait when the power-up control wait time
expires.
Manual output test The controller includes a manual output test sequence you can use to verify output
operation and associated output wiring. However, based on the current step in the
test sequence, the outdoor air damper may not be open. Refer to “Performing a man-
ual output test” on page 84.
Fan mode Off When a zone sensor fan mode switch determines the fan operation, the Off position
controls the unit Off and closes the outdoor air damper.
No power to the
controller
If the controller does not have power, the unit fan does not operate. For the controller
to operate normally, it must have an input voltage of 24 Vac. When the green status
LED is Off continuously, the controller does not have sufficient power or has failed.
Diagnostic present Specific diagnostics affect outdoor air operation. For more information, see Table 64
on page 93.
No power to the damper
actuator
If the outdoor air damper actuator does not have power, a normally open damper
remains closed. The damper actuator is powered separately from the controller's out-
put signal. If the damper actuator does not have 24 Vac, the controller cannot operate
the outdoor air damper.
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 devices,
the outdoor air damper may not work correctly.
Unit wiring The wiring between the controller outputs and the outdoor air damper must be
present and correct for normal damper operation.
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