In the event there is a need to run a Legacy Airflow product (CCT, or TC) in direct expansion (DX) mode while shutting down or doing maintenance on the chilled water (CW) system, below is the proper way to do a CW temp switch over.
Temp >> Down Arrow >> Down Arrow >> [You should see FreeCool: ECWS] >> Set the FreeCool OFF mode below the current water temp. This will cause the compressor(s) to come on as long as there is a demand for cooling.
NOTE: Attached are documents regarding External Chilled Water Supply (ECWS) and its operation. NOTE: These instructions are for a DG5.0 controller.