York YCIV - Compressors and Motors; Heat Exchangers; Operating Characteristics; Refrigerant Circuit Components

JOHNSON CONTROLS76
FORM 201.23-EG2 (713)
Guide Specications
controlsincludingcapacitycontroller,controlcenter,
motorstartingcomponents,andspecialfeaturesas
speciedhereinorrequiredforsafe,automaticopera-
tion.
C. OperatingCharacteristics:
1. Providelowambient controlandhigh ambient
options as required to ensure unit is capable
ofoperationfrom0°Fto125°F(-18°Cto52°C)
ambient.
2. Providecapacitycontrolsystemcapableofre-
ducingunitcapacityto(10%for2compressor
units,7.5%for3compressorunits,and5%for4
compressorunits)offullload.Compressorshall
startinunloadedcondition.Applicationoffactory
installedhotgasbypassshallbeacceptableas
requiredtomeetspeciedminimumload.
D. Cabinet: Unit panels, structural elements, control
boxes and heavy gauge structural base shall be
constructedofgalvanizedsteel.Unitpanels,control
boxesandstructuralbasearenishedwithabaked
onpowderpaint.Allpaintedsurfacesshallbecoated
withbakedonpowderpaintwhich,whensubjectto
ASTMB117, 1,000 hour, 5% salt spray test, yields
minimumASTM1654ratingof“6”.
E.Unitshallshipinonepieceandshallrequireinstaller
toprovideonlyasingleevaporatorinletandoutletpipe
connection. If achillermodelthat ships inmultiple
piecesisprovided,bidshallinclude allthe material
andeldlaborcostsforfactoryauthorizedpersonnel
toinstallatrimkittoconnectthepiecesaswellasall
interconnectingpipingandwiring.
2.02 COMPRESSORS AND MOTORS
A.Compressors: Shall be direct drive, semihermetic,
rotarytwin-screwtype,including:mufer,temperature
actuated‘off-cycle’heater,rain-tightterminalbox,dis-
chargeshut-offservicevalve,andprecisionmachined
castironhousingmountedonelastomericisolators.
Designworkingpressureofentirecompressor,suction
todischarge, shall be350psig(24 barg) orhigher.
CompressorshallbeU.L.recognized.
B.Motors: Refrigerant suction-gas cooled accessible
hermetic compressor motor, full suction gas flow
through0.006”maximummeshscreen,withinherent
internalthermaloverloadprotectionandexternalcur-
rentoverloadonallthreephases.
C.Lubrication: External oil separators with no moving
parts,450psigdesignworkingpressure,andULlisting
areprovidedonthechiller.Refrigerantsystemdiffer-
entialpressureshallprovideoilowthroughservice
replaceable,0.5micron,fullow,cartridgetypeoillter
internaltocompressor.Filterbypass,lessrestrictive
media,oroilpumpnotacceptable.
D. CapacityControl:Compressorsshallstartatminimum
load.  Provide Microprocessor control to command
compressorcapacitytobalancecompressorcapacity
withcoolingload.Whenrequiredtomeetminimum
load, hot gas bypass shall be factory installed and
integratedintostandardcontrolsystem.
2.03 REFRIGERANT CIRCUIT COMPONENTS
A.Each independent refrigerant circuit shall include:
liquidline shutoffvalvewith charging port, low side
pressurereliefdevice,removablecorelter-drier,sight
glasswithmoistureindicator,andelectronicexpansion
valve(EEV).
B. Chillermanufacturershallprovideindependentcircuit
foreachcompressortoprovidemaximumredundancy
duringchilleroperation.Ifequipmentdoesnothave
independent circuits per compressor, manufacturer
shall provide owner one spare compressor of each
uniquesize.
C. Dischargelinesshallbeprovidedwithmanualcom-
pressorshutoffservicevalves.Suctionlineshallbe
coveredwithclosedcellfoaminsulation.
2.04HEATEXCHANGERS
A.Evaporator:
1. Directexpansiontypeoroodedtypeshelland
tube evaporator with high efficiency copper
tubes.Independentrefrigerantcircuitsshallbe
providedpercompressor.
2. Constructed,tested, and stamped IAW appli-
cablesections ofASMEpressure vesselcode
forminimum235psig(16barg)refrigerantside
designworkingpressureand150psig(10barg)
watersidedesignworkingpressure.
3. Shellcoveredwith3/4”(19mm),exible,closed-
cell insulation, thermal conductivity of 0.26k
(BTU/HR-Ft
2
-°F/in.) maximum. Water nozzles
with grooves for mechanical couplings, and
insulatedbyContractorafterpipeinstallation.
4. Provide vent and drain ttings, and thermo-
staticallycontrolledheaterstoprotectto-20°F
(-29°C)ambientinoff-cycle.
B.Air-cooledCondenser:
1. Coils: Internally enhanced, seamless copper
tubes, mechanically expanded into aluminum