Diagnosing operational problems
CNT-SVX12C-EN 89
Table 30. Fan does 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. Refer to applicable wiring diagram.
Failed end device The fan motor and relay must be checked to ensure proper operation
Random start
observed
After power-up, the controller always observes a random start from 0 to 25 seconds. The
controller remains off until the random start time expires.
Power-up control-wait If power-up control-wait is enabled (non-zero time), the controller remains off until one of
two 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.
Cycling fan operation If configured to cycle with capacity, normally the fan cycles off with heating or cooling.
The heating/cooling sources cycle on or off periodically with the fan to provide varying
amounts of capacity to the zone.
Unoccupied operation Even if the controller is configured for continuous fan operation, the fan normally cycles
with capacity during unoccupied mode. While unoccupied, the fan cycles on or off with
heating/cooling to provide varying amounts of heating or cooling to the space.
Fan mode off If a local fan mode switch determines the fan operation, the off position controls the fan
off.
Requested mode off You can communicate a desired operating mode (such as off, heat, and cool) to the con-
troller. If off is communicated to the controller, the unit controls the fan off. There is no
heating or cooling.
Diagnostic present For information about diagnostics, see Table 28 on page 79.
No power to the con-
troller
If the controller does not have power, the unit fan does not operate. For the Tracer ZN517
controller to operate normally, it must have an input voltage of 24 Vac. If 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. If the unit configuration does not match the actual end device, the valves may
not work correctly.
Manual output test The controller includes a manual output test sequence you can use to verify output oper-
ation and associated output wiring. However, based on the current step in the test
sequence, the unit fan may not be on. Refer to the “Manual output test” on page 74.
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