Trane Tracer ZN.520 Installation Owner Diagnostics page 63

Table 31: Valves stay open
Probable cause
Freeze avoidance
Normal operation
DX/Electric Heat
Table 32: DX or electric output(s) does not energize
Probable cause
Unit wiring
Unit configuration
Diagnostic present
Manual output test
Freeze avoidance
Normal operation
Outside Air Damper
Table 33: Outdoor air damper stays closed
Probable cause
Unit wiring
Unit configuration
Random-start observed
Power-up control wait
Diagnostic present
Manual output test
Fan mode
OFF
UV-SVP01A-EN
Troubleshooting
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.
The controller opens and closes the valves to meet the unit capacity requirements.
The wiring between the controller outputs and the end devices must be present and correct for normal
operation.
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 unit may not work correctly.
A specific list of diagnostics affect compressor and electric heat operation. For more information see,
Tracer™ ZN.520 Unit Controller diagnostics, on page 52 for more information.)
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 DX or electric
outputs may be . For more information see, Manual Output Test, on page 48 for more information.)
OFF
When the fan is with no demand for capacity (0%) and the outdoor air temperature is below the
OFF
freeze avoidance setpoint, the controller disables compressors and electric heat outputs. This includes
mode when there is no call for capacity or any other time the fan is
UNOCCUPIED
The controller energizes the outputs only as needed to meet the unit capacity requirements.
The wiring between the controller outputs and the outdoor air damper must be present and correct for
normal damper operation.
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 damper may not work
correctly.
After power-up, the controller always observes a random-start from 5 to 30 seconds. The controller
remains until the random-start time expires.
OFF
When power-up control wait is enabled (non-zero time), the controller remains
conditions occurs:
1. The controller exits power-up control wait once it receives communicated information.
2. The controller exits power-up control wait once the power-up control wait time expires.
A specific list of diagnostics affects outdoor air operation. For more information see, Tracer™ ZN.520
Unit Controller diagnostics, on page 52 for more information.)
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 unit damper
may not be open. For more information see, Manual Output Test, on page 48 for more information.)
When a local fan mode switch (provided on the Trane zone sensor) determines the fan operation, the
position controls the unit
OFF
Possible Explanation
Possible Explanation
Explanation
and damper to close.
OFF
.
OFF
until one of two
OFF
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