York YCWS manual Guide Specifications - Cont, Microcomputer Control Center, Power Panel

Guide Specifications - Cont.

each unit. All piping will be ACR copper with brazed joints. The liquid line will include: a shutoff valve with charging port; sightglass with moisture indicator; thermal expan- sion valve; solenoid valve; and high-absorption remov- able-core filter drier. The entire suction line and the liq- uid line between the expansion valve and the cooler will be insulated with flexible, closed-cell, foam insulation.

MICROCOMPUTER CONTROL CENTER

Each unit shall contain a Microcomputer Control Center. All logic and controls shall be contained within a IP 32 (NEMA 1) cabinet with hinged outer door with positive acting latches. Inside shall be contained the “user friendly” and interactive inputs and outputs as follows: LCD display with light emitting diode back lighting for easy viewing of data and input buttons for DISPLAY (tem- peratures, pressure, etc.). ENTRY (enter/cancel inputs, advance day, change AM/PM), SETPOINTS (change), CLOCK (set time and schedule), PRINT (calling up op- erating and shutdown data), PROGRAM (change inputs from special conditions such as brine chilling) and UNIT ON/OFF.

The Microcomputer Control Center shall be capable of displaying the following: return and leaving liquid tem- perature; return and leaving condenser water tempera- ture (optional); low leaving liquid temperature cutout set- ting; system 1 and 2 percent full-load motor current and suction, discharge (optional) and oil differential pressures; liquid pulldown control range (selectable for 0.6°C to 1.1° C [1°F to 2°F] in one-tenth increments above the set- point); liquid pull-down rate sensitivity (0.3°C to 3.0°C [0.5°F to 5°F]/minute in 0.05°C [0.1°F] increments); anti-

recycle timer status; compressor run status; no cooling load condition; day; date; time; out of range message; daily and holiday scheduling of start/stop times; auto- matic or manual lead/lag status; lead compressor defini- tion; number of compressor starts and running hours; status of hot gas bypass valves (option), liquid line sole- noid valves, and water pump; last three fault shutdowns data; number of unloading steps; compressor load and unload timer status.

The operating program shall be stored in nonvolatile memory (EPROM) to eliminate chiller failure due to AC power failure/battery discharge. Programmed setpoints are retained in lithium battery – backed RTC memory for 5 years minimum.

Provisions shall be included for: pumpdown at shutdown and recycling pumpdown; a hard copy printout from a printer (by others) via an RS-232 electrical output; two steps of demand load limiting and remote chilled liquid reset from an external building automation system; unit alarm contacts; chilled water pump or remote air-cooled condenser control; or Remote Control with printout ca- pability (up to 2000 feet) via an RS-485 electrical output.

POWER PANEL

The power panel shall contain the compressor power terminals. U.L. recognized compressor motor starting contactors which meet l.E.C. requirements, current trans- former sensing for each compressor power source, for protection against under current, over current, imbal- anced current, single phasing compressor stall and voltage spikes.

48 YORK INTERNATIONAL