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| Tracer® ZN.520 |
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| Troubleshooting |
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Table 35. Fan outputs do not energize | ||
Probable Cause | Explanation | |
Random start observed | After power up, the controller always observes a random start from zero | |
| to 25 seconds.The controller remains off until the random start time | |
| expires. | |
Power up control wait | When power up control wait is enabled | |
| remains off until one of two conditions occur: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. | |
Cycling fan operation | 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. | |
Unoccupied operation | When the controller is in the unoccupied mode, the fan is cycled | |
| between high speed and off with capacity to maintain zone temperature | |
| control. | |
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. | |
Diagnostic present | A specific list of diagnostics affects fan operation. For more information, | |
| see the Diagnostics section. | |
No power to the | If the controller does not have power, the unit fan does not operate. For | |
controller | the Tracer® ZN.520 controller to operate normally, it must have an input | |
| voltage of 24 VAC. When the green LED is off continuously, the control | |
| ler 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 valves may not work correctly. | |
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. | |
| Refer to the Manual Output Test section. | |
Unit wiring | The wiring between the controller outputs and the fan relays and con | |
| tacts must be present and correct for normal fan operation. | |
85 |