User guide

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Corporate Office: 724.584.5500  Instant Access 24/7 (Parts and Service): 800.458.1960  Parts and Service: 814.437.6861
9
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whenpipingisoverheadwithatotalrunlengthover90feet(27M)thereshouldbeavalvein
thesupplylineandaninvertedPtrapwithavacuumbreakvalveinstalledasshowninFigure3.
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Figures4through9(onthefollowing
pages)providethepressuredrop
throughtheevaporatorandchilled
waterpipingassociatedwiththe
chiller.Usethisinformationfor
assistancewhensizingachilledwater
pump.Nominalchilledwaterflowrates
areprovidedinTable2andarebased
ona10°F(18°C)rangeacrossthe
evaporatorat50°F(10°C)LWTand85°F
(29.4°C)enteringcondenserwater.
Pumpcurvesfortypicaloptionalpumps
with60Hzpowerareinshownin
Figure10–EP2SeriesPumpCurves.
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Theminimumflowratesarerequiredtopreventfoulingandtoensurethechillerstayswithin
normalrefrigerantoperatingconditions.
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IftheprocessflowrequirementislowerthantheminimumflowlimitationshowninTable2(on
thenextpage),multiplesmallerchillersmaybeused.Anotheralternativeistouseaprimary
pumpingloopdesignedforlowerflowatahighertemperaturerisethroughtheprocessanda
secondarypumpingloopdesignedforahigherflowandlowertemperaturedropthroughthe
chiller.Ifasecondarypumpingloopisused,maintainthemixedtemperatureofcoolant
enteringtheevaporatorataminimumofatleast5°F(2.8°C)abovethesetpointofthechiller.
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ThemaximumflowlimitationshowninTable2isthetheoreticallimitsof
thechillerbasedupon
a5°F(2.8°C)dropacrossthechiller;however,theseflowsresultinimpracticalpressuredrops
throughthechillerandarethereforenotlikelyforasystemdesign.Iftheprocessflow
requirementishigherthanthemaximumflowlimitation,abypassaroundthechillermaybe
used.Anotheralternativeistouseaprimarypumpingloopdesignedforhigherflowandlower
temperaturerisethroughtheprocessandasecondarypumpingloopdesignedforlowerflow
andhighertemperaturedropthroughthechiller.Ifasecondarypumpingloopisused,maintain
themixedtemperatureofcoolantenteringthechillerataminimumofatleast5°F(2.8°C)
abovethesetpointofthechiller.
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Theuseofvaryingchillerflowsissometimesnecessary;however,itishighlyrecommendedto
useadedicatedevaporatorcirculationpumptoprovideincreasedsystemstability.Thecontrols
ofthechillerareveryadaptable
andarecapableofadjustingtovariationsintheflowofwater
throughthesystemandwillloadandunloadcompressor(s)asneededtomaintaintightcontrol
oftheleavingwatertemperatureofthesystem.Ifthechillerflowisvaried,theminimumfluid
loopvolumemustbeinexcessof3gallonsofcoolantpertonofcooling(3.2LperkW)andthe
Figure 3 – Recommended Overhead Piping
NOTE:
If piping is above chiller and exceeds 90 feet in total
length, install an inverted P-trap and vacuum break
valve in return line and add a check valve to the
supply line.
Check valve
1/2 inch vacum break valve
12 inches above highest
point in piping system