User guide

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isfullyloadedbytheheatfromtheprocess.IfthePartialLoadLEDstayson,thechillerhasa
verysmallloadonitfromtheprocess.Ifthislowloadconditionpersists,theToProcess
temperaturemaybegintodropbelowtheSetpointtemperature,eventuallycyclingoff
compressor(s).
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Compressor1LED
TheCompressor1LEDissolidgreenwhileCompressor#1isrunning.Itwillflashredifa
compressoroverloadconditionexists(onlychillerswiththefollowingnominaltonnages:15,25,
30,35,40).Compressor#1willbeenabledwheneverthetemperatureofwaterleavingthe
chillerrisesabovetheSetpoint
byanamountequaltothecontrolparameterPS1(Compressor
#1PositiveSpread).PS1isequalto2°Fbydefault.Thecompressorwillbedisabledifthe
temperatureofwaterleavingthechillerdropsbelowtheSetpointbyanamountequaltothe
controlparameternS1(Compressor#1NegativeSpread).TheparameternS1issetto4°Fby
default.SeetheProgramMenusectionforinstructionsonhowtoadjustPS1andnS1.To
preventexcessivecompressorcycling,thecontrolboardhasacompressoranti‐cycledelay
timerbuiltin.Anytimethatacompressorisbeingpreventedfromturningonbytheanti‐cycle
timer,theCompressorRecycleLEDwillbelit.
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Compressor2LED
TheCompressor2LEDissolidgreenwhileCompressor#2isrunning.Compressor#2isonly
presentonchillers20tonsandlarger.Itwillflashredifacompressoroverloadconditionexists
(onlychillerswiththefollowingnominaltonnages: 15,25,30,35,and40).Compressor#2will
beenabledwheneverthetemperatureofwaterleavingthechillerrisesabovetheSetpointby
anamountequaltothecontrolparameterPS2(Compressor#2PositiveSpread).PS2isequalto
3°Fbydefault.Thecompressorwillbedisabledifthetemperatureofwaterleavingthechiller
dropsbelowtheSetpoint
byanamountequaltothecontrolparameternS2(Compressor#2
NegativeSpread).TheparameternS2issetto5°Fbydefault.SeetheProgramMenusection
forinstructionsonhowtoadjustPS2andnS2.Topreventexcessivecompressorcycling,the
controlboardhasacompressoranti‐cycledelaytimerbuiltin.Anytimethatacompressoris
beingpreventedfromturningonbytheanti‐cycletimer,theCompressorRecycleLEDwillbelit.
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TemperatureLimitLED
TheTemperatureLimitLEDwillflashyellowifadeviationwarningexists.Itwillflashredifa
highorlowcriticaltemperaturesafetyalarmconditionexists.
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