SterlingTEK A0551797 manual Staging, Alarms, Lead-Lag Compressors, Lead-Lag Pumps

4 Sequence Of Operation

4-1 Staging

1.The system uses a PID control algorithm to regulate the chilled water temperature. As the required control effort increases or decreases, the system compressors are turned on or off to keep the temperature at the specified set-point

2.Compressor anti-recycle time is three (3) minutes.

4-2 Alarms

If a fault occurs, that compressor or circuit is deactivated. The load will automatically shift to any other compressors that are currently ON-LINE, but not running. Lead/Lag rotation will continue to function. Compressors that are faulted will be removed from the rotation order.

4-3 Lead-Lag Compressors

The system automatically rotates the compressor order to generate a Lead/Lag rotation. Any time a compressor is faulted or manually taken OFF-LINE, it will be removed from the Lead/Lag rotation.

Once the fault is cleared or manually put ON-LINE, the compressor is returned to the Lead/Lag rotation at the end of the rotation order.

4-4 Lead-Lag Pumps

The system automatically rotates the pump order to generate a Lead/Lag rotation. Any time a pump is faulted or manually taken OFF-LINE, it will be removed from the Lead/Lag rotation. Once the fault is cleared or manually put ON-LINE, the pump is returned to the Lead/Lag rotation at the end of the rotation order.

SSC Series Central Chilling Stations Page 27 of 86