Trane Tracer ZN.520

CNT-SVX04A-EN
Troubleshooting
96
Questionable unit operation
Table 61 Fan outputs do not energize
Probable cause Explanation
Unit wiring The wiring between the controller outputs and the fan relays and
contacts must be present and correct for normal fan operation.
No power to the
controller
If the controller does not have power, the unit fan does not
operate. For the Tracer ZN.520 zone controller to operate normally,
it must have an input voltage of 24 VAC. When the green LED is off
continuously, the controller does not have sufficient power or has
failed.
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 fans 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.
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 once it receives
communicated information.
The controller exits power-up control wait once the power-up
control wait time expires.
Diagnostic present A specific list of diagnostics affects fan operation. For more
information, see Table on page 92.
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 unit fan may
not be on. See “Manual output test” on page 88.
Fan mode off When a local fan mode switch (provided on the Trane zone sensor)
determines the fan operation, the off position controls the unit off.
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.
Unoccupied
operation
When the controller is in the unoccupied mode, the fan is cycled.
Cycling fan
operation/continuous
The controller operates the fan continuously when in the occupied,
occupied standby, or occupied bypass mode. When the controller
is in the unoccupied mode, the fan is cycled between high speed
and off with capacity.