Trane LO - Manual (Page 57)

UNT-IOM-6 57
Tracer
®
ZN.010
and ZN.510
Table 19. Fresh Air Damper Stays Closed
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 the “Manual Output Test” section on Page 51.
Diagnostic present A specific list of diagnostics effects fresh air damper operation. For more
information, see the “Diagnostics” section on page 50.
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 If the controller does not have power, the fresh air damper does not operate. For
controller 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 in the Appendix of this manual.