Tracer® ZN.010
and ZN.510
Table 16. Valves Stay Closed
Probable Cause | Explanation |
Normal operation | The controller opens and closes the valves to meet the unit capacity require- |
| ments. |
Requested mode: off | It is possible to communicate the operating mode (such as off, heat, and |
| cool) to the controller. When off is communicated to the controller, the unit |
| controls the fan to off. The unit is not capable of heating or cooling when the |
| controller is in this mode. |
Valve override | The controller can communicate a valve override request. This request effects |
| the valve operation. |
Manual output test | The controller includes a manual output test sequence to verify analog and |
| binary output operation and the associated wiring. However, based on the |
| current step in the test sequence, the valves may not be open. Refer to the |
| “Manual Output Test” section on page 51. |
Diagnostic present | A specific list of diagnostics affects valve operation. For more information, see |
| the “Diagnostics” section on page 50. |
Sampling logic | The controller includes entering water temperature sampling logic that |
| automatically invokes during |
| the entering water temperature is either too cool or too hot for the desired |
| heating or cooling mode. Refer to the “Entering Water Temperature Sampling” |
| section on page 41. |
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 valves may not work correctly. |
No power to the | If the controller does not have power, the valves do not operate. For the controller |
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 the controller has failed. |
Unit wiring | The wiring between the controller outputs and the valve(s) must be present and |
| correct for normal valve operation. Refer to the typical unit wiring diagrams in the |
| Appendix of this manual. |
54 |
