Trane CGWF, CCAF manual Human Interfaces, Safety Controls, Standalone Controls

Controls

Human Interfaces

The Trane water-cooled 20-60 ton scroll CGWF chiller offers an easy-to-use operator interface panel, the DynaView.

DynaView is an LCD touchscreen display that is navigated by file tabs. This is an advanced interface that allows the user to access any important information concerning setpoints, active temperatures, modes, electrical data, pressures, and diagnostics.

Safety Controls

A centralized main processor offers a higher level of machine protection. Since the safety controls are smarter, they limit compressor operation to avoid compressor or evaporator failures, thereby minimizing nuisance shutdown. Tracer™ Chiller Controls (CH530) directly senses the control variables that govern the operation of the chiller: evaporator pressure and condenser pressure. When any one of these variables approaches a limit condition where damage may occur to the unit or shutdown on a safety, Tracer Chiller Controls takes corrective action to avoid shutdown and keep the chiller operating. This happens through compressor shedding. Tracer Chiller Controls optimizes total chiller power consumption during normal operating conditions. During abnormal operating conditions, the microprocessor will continue to optimize chiller performance by taking the corrective action necessary to avoid shutdown. This keeps cooling capacity available until the problem can be solved. Whenever possible, the chiller is allowed to perform its function; making chilled water. Overall, the safety controls help keep the building or process running and out of trouble.

Figure C1. DynaView operator interface

Standalone Controls

Interface to standalone units is very simple; only a remote auto/stop 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.

Standard Features

•External Auto/Stop — A jobsite provided contact closure will turn the unit on and off.

•Chilled Water Flow Interlock — A jobsite provided contact closure from a chilled water pump contactor and/or a flow switch is required and will allow unit operation if a load exists and flow is proven. This feature will allow the unit to run in conjunction with the pump system.

•Emergency Stop — A jobsite supplied contact opening wired to this input will turn the unit off and require a manual reset of the unit microcomputer. This closure is typically triggered by a jobsite supplied system such as a fire alarm.

•Chilled Water Pump Control — Unit controls provide an output to control the chilled water pump(s). One contact closure to the chiller is all that is required to initiate the chilled water system.

•Chilled Water Temperature Reset — Reset can be based on return water temperature or outdoor air temperature (optional).

•Condenser Water Pump Control — Unit controls provide an output to control the condenser water pump(s). One contact closure to the chiller is all that is required to initiate the chilled water system.

•Condenser Water Flow Protection — A jobsite supplied contact closure from a flow switch or pressure switch is required and will shut down the unit if flow is lost.

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