Model YPC Two-Stage Steam-Fired Absorption ... - Usair-eng.com

Mechanical Specifications - continuedWarning Conditions – The MicroComputer ControlCenter provides a warning annunciation, when appropriate,limits heat input under the following conditions:low refrigerant temperature, high generator pressure ortemperature, high or low entering condenser water temperature,purge pump current overload, faulty solutiondilution temperature sensor.Safety Controls – The Control Center includes uniquesafety logic designed to protect the Two-Stage chiller fromdamaging malfunctions. Complete safety annunciationis displayed for each shutdown by pressing the statuskey. This information includes day, time and reason forshutdown. These include: solution – or refrigerant – pumpthermal or current overload, low refrigerant temperature,first-stage generator high pressure or temperature, loss ofchilled water flow, power failure, auxiliary safety shutdown,incomplete dilution cycle and power failure if manual restartafter power failure is selected.Operating Controls – Background messages aredisplayed while the unit is running to signal operatorof controlling conditions such as leaving chilled watertemperature control and noncritical sensor error. Systemcycling messages display day, time, cause of cyclingshutdown, and autostart indication. These include loss ofcondenser water (or hot water) flow, low-leaving chilledwater (or high leaving hot water) temperature, and powerfailure (when autostart is selected).Digital programming of operating setpoints from the keypadinclude leaving chilled water (or hot water) temperature,pulldown demand limiting, remote steam demandlimit, remote reset temperature range, and daily start/stopscheduling of chiller and water pumps with separate holidayschedule.Security access code is provided for operator to programsetpoints or to choose local, remote, or service modesof operation. Manual control of the steam valve positionand all pumps is provided through separate buttons in theservice mode of operation.the RS232 port in the control center to obtain data logs.This can be accomplished at any time by pressing the“Print” button on the control center, or automatically atpredetermined intervals by programming the panel’sdata logger. The printer will automatically record time andcause of any safety or cycling shutdown along with allchiller operating data monitored by the panel just prior toshutdown. A “History Print” button also allows the printoutof the last four causes of cycling or safety shutdowns plusoperating data for each shutdown.BAS Interface – The MicroComputer Control Center iscompatible with remote Building Automation Systems(BAS). The standard design allows remote start andstop; leaving chilled-water temperature reset and steamdemand limit through PWM signal; and “ready-to-start,”“unit running,” “safety” and “cycling” shutdown statuscontact. For designed-in features and reliability, YORKprovides a full line of BAS controls.FACTORY LEAK TESTEach YPC unit is subjected to a series of four rigorousleak tests, culminating in a vacuum leak test measuredby a mass spectrometer and conducted while the unit isimmersed in an atmosphere of low-density helium.CODES AND STANDARDS• ASME Boiler and Pressure Vessel Code - Section VIIIDivision 1• ARI 560-92• NEC – National Electrical Code• OSHA – Occupational Safety and Health ActPAINTExterior surfaces are protected by an initial coat of redoxide primer with a single finish coat of Caribbean-blueair-drying, high-solids, enamel machinery paint.Data Logging – All operating and setpoint informationcan be transmitted to a remote printer (by others) through10 JOHNSON CONTROLS