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Troubleshooting
Questionable Unit
Operation
Table 16: 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 status. Normally, the outdoor air damper is open
during occupied mode when the fan is running and closed during unoccupied
mode. Refer to the outdoor air damper section on page 8.
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 is an attempt to bring the space under control as quickly as
possible.
Requested mode off.
The desired operating mode (such as off, heat and cool) can be communicated to
the controller. When off is communicated to the controller, the unit closes the
outside air damper.
Manual output test.
The controller includes a manual output test sequence that may be used 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 the
manual output overrides on page 9.
Diagnostic present.
A specific list o f diagnostics affects outdoor air damper operation, depending
whether the unit is configured as heat pump. For more information, see the
Diagnostics section on page 27.
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 outdoor air damper may not work correctly.
No power to the controller.
If the controller does not have power, the compressor does not operate. For the
ZN510 controller to operate normally, a voltage input of 24 VAC 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 outdoor air damper must be
present and correct for normal outdoor air damper operation.