Dometic SmartStart III - Refrigerant Low - Low; Analog Inputs; High Limit Temperature; Freeze Temperature

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REFRIGERANT LOW – LOW SIDE PRESSURE L IM I T(Optional) 
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ThePLCwillimmediatelyacknowledgeanopencircuitifthelowpressureswitchistrippedandde‐energizethecompressor.Itwill
recordanddisplaylowpressurefaultonthealarmscreen.IfthePLC detectsalowpressurefaultduringoperation,aLPfaultwillbe
displayedandrecorded.
ThePLCwillnotallo wthecompressorrelaytobere‐energized,untilswitchisintheclosedposition.
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ThefaultmustbemanuallyacknowledgedviathePLCandclearedpriortore‐enabling thesystemorstage.
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ANALOGINPUTS 
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HIGH LIMIT T E M P ERA TU RESETPOINT 
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ThehighlimittemperaturesensoriscontinuouslymonitoredwhetherinCooling,ReverseCycleorElectricHeatmode.
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Thissensorisusedtodetectahightemperatureconditioninthesupplywaterfromthechiller.Ifthech illedwatertemperatureissensed
tobegreaterorequalto125°F(51.7°C),allenabledcompressorrelayswillbede‐energized,turningoffthecompressor(s)ifoperating
inreversecyclemode.If
electricheatisbeingused,allenabledheaterrelayswillbede‐energized,turningofftheheatingelement(s).
Asthetemperaturefalls,thecompressororelectricheatrelaywillre‐energizewhenthetemperaturereaches110°F(43.3°C).
Ahightemperaturefaultwillberecordedanddisplayedifthesystemexceeds
thealarmsetpoint.Inahightemperaturesituation,PLC
willnotallowthecompressororelectricheatrelaytobeenergized.Thefaultmustbemanuallyacknowledgedontheactivealarm
screenandclea redpriortore‐enablingthesystemorstage.
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Ifatemperaturesensorisbadornotconnected,thePLCwilldisplayanalarmforthatsensor.
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FREEZE T EM P E R A T U RESETPOINT 
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ThelowlimittemperaturesensoriscontinuouslymonitoredwhetherinCooling,ReverseCycleorElectricHeatmode.
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Thissensorisusedtodetectafreezeconditioninthesu pplywaterofthechiller.Ifthechilledwatertemperatureissensedtobeequalto
or less than38°F(3.3°C),thenthe compressor relaywill be de‐energized,shuttingoff thecompressor. As the temperature rises, the
compressorrelaywillre‐energizewhenthetemperaturereaches42°F(5.6°C).
Alowtemperaturefaultwillberecordedanddisplayedifthesystemfallsbelowthealarmsetpoint.Inalowtemperaturesituation,
PLCwillnotallowthecompressororelectricheatrelaytobeenergized.Thefaultmustbemanually
acknowledgedontheactivealarm
screenandcleare dpriortore‐enablingthesystemorstage.
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Ifatemperaturesensorisbadornotconnected,thePLCwilldisplayanalarmforthatsensor.
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CondenserFreezeProtection(Optional)
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Thesystemisequippedwithatemperaturesensormountedtothecondensercoil.Thissensoristheretosensethecoiltemperature.In
heatmodeifthecoiltemperaturedropsbelow40°F,thePLCcontrolswillautomaticallylowerthespeedofthecompressortohalfthe
speedthatitwas
currentlyrunning.Thedisplaywillindicate“FreezeDefrost”whileperformingthisoperation.
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PRESSURE TR AN SD UCERS 
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SUCTION Pressure 
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ThesuctionpressureiscontinuouslymonitoredbythePLC.Ifthesuctionpressureisbelowthealarmsetpointforlongerthanthe
programmedtimedelay,afaultwilloccur .Thislowsuctionfaultwillberecordedanddisplayedonthealarmscreen.
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ThefaultmustbemanuallyacknowledgedviathePLCandclearedpriortore‐enablingthesystemorstage.
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DISCHARGE Pressure 
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ThedischargepressureiscontinuouslymonitoredbythePLC.Ifthedischargepressureisabovethealarmsetpointforlongerthanthe
programmedtime,afaultwilloccur.Thishighpressurefaultwillberecordedanddisplayedonthealarmscreen.
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ThefaultmustbemanuallyacknowledgedviathePLCandclearedpriortore‐enablingthesystemorstage.
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