Stand-Alone Unit
Figure 28-1 — Stand-Alone Unit
Interface to stand-alone units is very simple; only a remote auto-stop or chilled water flow interlock signal for scheduling is required for unit operation. Signals from the chilled water pump contactor auxiliary or a flow switch are wired to the chilled waterflow interlock. Signals from a time clock or some other remote device are wired to the external auto-stop input. Unit controls do not provide an output to turn pumps on and off.
Required Features
- External Auto/Stop (Standard) - or -
- Chilled Waterflow Interlock (Standard)
Trane Integrated Comfort™ System Interface
Figure 28-2 — Tracer® ICS System Interface Schematic
A single twisted pair of wires tied directly between the CGA unit and a Tracer ® system provides control, monitoring and diagnostic capabilities. Control functions include auto/stop, compressor operation lockout for kw demand limiting. In addition, the Tracer system can provide sequencing control for two or three CGA units on the same chilled water loop. Pump sequencing control can be provided from the Tracer system also. Sequencing of two CGA’s can be accomplished with the DDC Chiller Sequencer.
Required Features
- Unit Temperature Controller (Standard)
- ICS Interface Panel
External Trane Devices Required
- Tracer 100 System - or -Tracer L System