Airxcel Marvair LL357D4 User manual

P/N 01661
Lead/Lag Controller
Model LL357D4
Operational Specifications
• ThermostatRange:45ºFto90ºF(7ºC
to32ºC)
• Accuracy:±1ºF(±½ºC)
• ChangeoverTemperatureDifferential
(separationbetweentheheatset
pointandthecoolsetpoint):2ºFto
9ºF(1.0ºCto4.5ºC)
• FirstStageTemperatureDifferential
(numberofdegreesbetweentheset
pointtemperatureandthe“turnon”
temperature):1ºFto3ºF(.5ºCto
1.5ºC)
• SecondStageTemperatureDifferential
(numberofdegreesbetweenwhen
stage1turnsonandwhenstage2
turnson):1ºFto6ºF(.5ºCto3.0ºC).
• MinimumCoolTemperatureSetPoint:
Adjustablefrom45ºFto75ºF(7ºCto
24.0ºC).
• MaximumHeatTemperatureSet
Point:Adjustablefrom55ºFto90ºF
(13ºCto32.0ºC)
• StagedOFFOutputs:Airconditioners
willturnoffindependently.
Electrical Specifications
• Compatiblewithstandard24-voltAC,
2stageheating/coolingsystems.
• 24Voltcontrol(18to30VAC).
• 1ampmaximumperterminal.
• 4ampmaximumtotalload.
Ease of Use
• Backlightingofthelargedisplay
makestheLiquidCrystalDisplay
(LCD)easytoread.
• Mostfrequentlyusedkeysarelocated
bytheLCDforquick&easyaccessto
information.
• Easyinstallation,setupandsystem
testssavestime.
• Setpointsarepermanentlyheldin
memoryandretainedduringpower
outages-nobatteriesrequired.
• Programmingnotrequired.
• Digitaldisplayshowstemperaturein
°For°C.
• RoomTemperatureOffset:Usedto
calibratedisplayedroomtemperature
withactualroomtemperature
• StatusIndicatorLight:Indicateswhich
stageisrunning.Greenlightmeans
cooling&redlightmeansheating.
Model LL357D4 Lead/Lag Controller
TheMarvair®LL357D4isacompletecontrolpackage
designedtooperateafullyorpartiallyredundantair
conditioningsystem.Itconsistsofatwo-stageheatand
coolelectronicthermostatandasolidstatetimer.It
canbeusedwitheithertheMarvairComPac®Ivertical
packagedwallmountairconditioner,ouruniqueComPac®
IIairconditionerwithbuilt-ineconomizerandmanyofthe
MarvairEnvironmentalControlUnits(ECU).TheLL357D4
providesenvironmentalcontrolandthesecuritydemanded
bythecommunicationshelterindustryforaback-up
unit.Thelead/lagcontrollerinsuresequalwearonboth
airconditionerswhileallowingthelagunittoassistupon
demand.Phasingofairconditionersisnotrequiredfor
properoperation.Theenvironmentallysafe,mercury-freeLL357D4isfactorywired,
testedandmountedinanenclosureforquickinstallation.TheLL357D4whenused
withtheheatpumpadapter,ModelLL357H,providescontrolofredundantheatpump
systems.RefertotheHeatPumpAdapterProductBulletinfordetails.
Specification/Features
LL357D4 PDS 4.2011 rev. 1

LL357D4 PDS, 4.2011 2
Specification/Features (cont'd)
Ease of Installation
• Wiringconnectionsinsensitivetothephasingof
theairconditioners.
• Temperaturesensorbuiltintotheunit(optional
remotesensoravailable).
• Easyterminalconnectionsforthermostatwire.
Timing Device
• Solidstatetimerwithboth3.5and7day
changeovercapability.Timingaccuracy±5%.
• Momentarypushbuttonforaccelerated
manualtimeradvance.(7seconds=7days)
• Lightemittingdiodesindicatepoweronand
identifiestheleadunit.
Enclosure
• 16gaugeappliancewhite,pre-painted
aluminum.
• Provideslowprofilethermostatmounting.
• Openingsincoverfor“LED”indicationofpower
onandforleadunit.
• Doublesasjunctionboxforcontrolwiringtoair
conditioners.
Low Voltage Wiring
1. Allwiringmustcomply
withlocalcodesand
ordinances.
2. Disconnectpowerto
preventelectricalshock
orequipmentdamage.
3. Ondualunits,wire
theairconditioners
accordingtothewiring
detail.
4. Providepowertothe
controller.
NOTE:
• Terminals 5 and 7 on the
ComPac®I & ComPac®II
air conditioner’s terminal
board are dry contacts
which can be used for
remote signalling in the
event of equipment cut-
off on refrigerant pressure
limit.
•For continuous indoor fan
operation, install a jumper
between terminals 8 and
3 and remove jumper
between 1 and 3.
•Also, terminals 8 and 10
can be connected to a
normally closed smoke
or fire detector to cause
equipment shutdown
when the circuit is opened.
(Remove factory jumper.)
LED Operation
•Green (middle light) means
power on to both units.
•Red (left and right lights)
indicates the lead unit.

3 LL357D4 PDS, 4.2011
Sub-base Illustration
Important Safety Precautions
WARNING!:Always turn off power at the main power supply before installing, cleaning, or
removing thermostat.
• Thisthermostatisfor24VACapplicationsonly;donotuseonvoltagesover30VAC
• Donotshortacrossterminalsofsystemcontroltotestoperation;thiswilldamageyourthermostat
andvoidyourwarranty
• Allwiringmustconformtolocalandnationalelectricalandbuildingcodes
• Usethisthermostatonlyasdescribedinthismanual
To Install LL357D4 Thermostat/Controller
ELECTRICAL SHOCK HAZARD – Turn off power at the main service panel by removing the
fuse or switching the appropriate circuit breaker to the OFF position before removing the
existing thermostat.
IMPORTANT:Thermostatinstallationmustconformtolocalandnationalbuildingandelectricalcodes
andordinances.
Note:Mountthethermostataboutfivefeetabovethefloor.Donotmountthethermostatonan
outsidewall,indirectsunlight,behindadoor,orinanareaaffectedbyaventorduct.
1. Turnoffpowertotheheatingandcoolingsystembyremovingthefuseorswitchingoffthe
appropriatecircuitbreaker.
2. Putthermostatbaseagainstthewallwhereyouplantomountit(Besurewireswillfeedthroughthe
wireopeninginthebaseofthethermostat).
3. Marktheplacementofthemountingholes.
4. Usingadrillbit,drillholesintheplacesyouhavemarkedformounting.
5. Alignthermostatbasewithmountingholesandfeedthecontrolwiresthroughwireopening.
6. Usescrewstomountthermostatbasetowall.
7.Insertstripped,labeledwiresinmatchingwireterminals.SeeWiringDiagrams.CAUTION!:Besure
exposedportionofwiresdoesnottouchotherwires.
8.Tightenscrewsonterminalblock.Gentlytugwiretobesureofproperconnection.Doublecheckthat
eachwireisconnectedtotheproperterminal.

LL357D4 PDS, 4.2011 4
9.Sealholeforwiresbehindthermostatwithnon-flammableinsulationorputty.
10.Replacecoveronthermostat.
11.Turnonpowertothesystematthemainservicepanel.
12.Testthermostatoperationasdescribedin“TestingtheThermostat”(Page6).
Remote Sensor Installation (optional)
1. Removecoverfromremotesensorhousing.
2. Selectanappropriatelocationformountingtheremotesensor.
3. Mountremotesensorunitusinghardwareprovided.
4. Installtwowiresbetweenremotesensorandthermostat(useshieldedcablethatisadequately
grounded).
• Wire1shouldrunbetween
theS1terminalonthe
thermostatandtheS1
terminalontheremote
sensor
• Wire2shouldrunbetween
theS2terminalonthe
thermostatandtheS2
terminalontheremote
sensor
5. Disablethemainsensor(R12)
onthethermostatbycuttingit
fromthecircuitboard.
Configuration Mode
TheconfigurationmodeisusedtosettheLL357D4thermostattomatchyourheating/coolingsystem.
TheLL357D4functionswithairconditionerswithelectricheatsystems.
ToconfiguretheLL357D4,performthefollowingsteps:
1. VerifythattheLL357D4isintheOFFmode.PresstheSYS(left)buttonuntilmode
displays.
2. Removethecoverofthethermostatbygentlypullingnearoneofthecornersatthe
topofthethermostat.
3. PresstheCONFIGbuttonforonesecondwhilethethermostatisintheOFFmode.
 UsetheUpandDownbuttonstochangesettingswithineachscreen.
 PresstheRightbuttontoadvancetothenextscreen.
 PresstheLeftbuttontoreturntopreviousscreen.
4. ToexitConfigurationMode,presstheCONFIGswitchfor1second.
Configuration Mode Settings
ThesetupscreensfortheConfigurationModefollow:
1. TemperatureScale(°For°C)
ChooseFahrenheitorCelsius.
 PresstheUporDownbuttontoselectscale.
 PresstheRightbuttontoadvancetothenextscreen.
2. 1st Stage Temperature Differential(1°Fto5°F)(0.5°Cto2.5°C)
Setthenumberofdegreesbetweenyour“setpoint”temperatureandyour“turnon”temperature.
Marvairrecommends2ºF.
 PresstheUporDownbuttontosetdifferentialvalue.
 PresstheRightbuttontoadvancetothenextscreen.

5 LL357D4 PDS, 4.2011
3. 2nd Stage Temperature Differential(1°Fto5°F)(0.5°Cto2.5°C)
Setthenumberofdegreesbetweenwhenstage1turnsonandwhenstage2turnson.Marvair
recommends2ºF.
 PresstheUporDownbuttontoselectdifferential.
 PresstheRightbuttontoadvancetothenextscreen.
4. Staged Off Outputs
Selectwhethertheoutputsforheatingandcoolingarestagedoffindependentlyoraresatisfied
simultaneously.Select“1”,outputsstagedindependently.
 1=outputsstagedoffindependently
 0=outputsoffsimultaneously
 PresstheUporDownbuttontoselect.
 PresstheRightbuttontoadvancetothenextscreen.
5. Minimum Deadband(1°Fto9°F)(1°Cto5°C)
SettheminimumseparationbetweenheatsetpointandcoolsetpointinAutoChangeoverMode.
Marvairrecommends3ºF.
 PresstheUporDownbuttontosetdeadbandvalue.
 PresstheRightbuttontoadvancetothenextscreen.
6. System–Setforheatpump,non-HeatPump(airconditioner),reversingvalveoperationand
numberofcompressorsinyoursystem.Setupfor“Non-HeatPump”andTypeof
Heat“Electric”.
 PresstheUporDownbuttontoselectscale.
 PresstheRightbuttontoadvancetothenextscreen.
 PresstheUporDownbuttontoselect.
 PresstheRightbuttontoadvancetothenextscreen.
7. Auxiliary Delay ON–(0-30minutes)
Setthedelaytimeinminutesforauxiliaryheattobelockedoutafteracallforsecondstage.This
extrasavingsfeatureisusedtotemporarilylockoutauxiliaryheatdevices,allowingjustheat
pumptotrytosatisfyheatcall.Setto0minutes.
 PresstheUporDownbuttontoselect.
 PresstheRightbuttontoadvancetothenextscreen.
8. Lockout(0-8°,COOL-HEAT)
Selectthenumberofdegreessettemperaturecanbechangedduringkeypadlockout.COOL-
HEATlockoutallowsadjustmentofthesettemperaturestothemaximumheatsettemperature
selectedinStep9andminimumcoolsettemperatureselectedinStep10.
 Note:Themodecannotbechangedwhenthethermostatislocked.
 PresstheUporDownbuttontoselect.
 PresstheRightbuttontoadvancetothenextscreen.
Choose System Reversing
Valve Active
Number of Compressors
or Compressor Stages
Type of
Heat
HeatPump
HP O 1
HP b 1
HP O 2
HP b 2
Non-Heat
Pump
Heat Gas
Heat Electric

LL357D4 PDS, 4.2011 6
Configuration Mode Settings (cont'd)
9. Maximum Heat Setpoint(45°Fto90°F)(7°Cto32°C)
 Adjusttocontrolthemaximumheatsettemperatureallowed.Marvairrecommendsamax.heat
 setpointof78ºF(25.6ºC)
 PresstheUporDownbuttontoselect.
 PresstheRightbuttontoadvancetothenextscreen.
10. Minimum Cool Setpoint(45°Fto90°F)(7°Cto32°C)
 Adjusttocontroltheminimumcoolsettemperatureallowed.Marvairrecommendsaminimum
 coolsetpointof68ºF(20ºC).
 PresstheUporDownbuttontoselect.
 PresstheRightbuttontoadvancetothenextscreen.
11. Room Temperature Offset(+9°Fto-9°F)(+4.5°Cto-4.5°C)
 Adjusttocalibratedisplayedroomtemperaturetomatchactualroomtemperature.Note:When
 notsetto0,ºwilldisplay.
 PresstheUporDownbuttontoselect.
 PresstheRightbuttontoadvancetothenextscreen.
12. Temperature Sensor (1-3)
 1.Onlyon-boardsensordeterminesroomtemperature.
 2.Onlyremotesensordeterminesroomtemperature.
 3.Averagetemperatureofon-boardandremotesensor.
 Note:Ifthereisnoremotesensor,option1mustbeselected.
 PresstheUporDownbuttontoselect.
 PresstheRightbuttontoadvancetothenextscreen.
13. Cooling Fan Delay Off Time(0,30,60,90seconds)
 Selectthefanpurgetimeforcooling.Marvairrecommends0seconds.
 PresstheUporDownbuttontoselect.
 PresstheRightbuttontoadvancetothenextscreen.
14. Status Indicator Light (Led0,1,2)
 Marvairrecommends1.
 0=Statusindicatorneveron
 1=Statusindicatoronwithfirststage
 2=Statusindicatoronwithsecondstage
 PresstheUporDownbuttontoselect.
PresstheCONFIGbuttonfor2secondstoexitconfiguration.

7 LL357D4 PDS, 4.2011
Testing the Thermostat
Note: The LL357D4 does not require the units to be in phase.
Procedure: (A/C Testing with LL357D4 Lead/Lag Control for Two Units)
UP-Usedtoincreasethetime,settemperaturesandtoadjust
configurationsettings.
DOWN-Usedtodecreasethetime,settemperaturesandto
adjustconfigurationsettings.
SYS(left)-UsedtochangefromOFF,HEAT,COOLandAUTOchangeovermodes.
RIGHT-Usedtoturnonandofftheindoorfan.
UP, SYS and RIGHT-Heldinsimultaneouslyfor10secondstolockandunlockthethermostat.
DOWN and SYS-Pressedsimultaneouslytodisplayoutdoortemperatureifoutdoorremotesensoris
connected.
1. Setthecoolingtemperatureonthewallthermostattoapointhigherthantheambienttemperature.
Settheheatingtemperaturetoatemperaturethatislowerthantheambienttemperature.Turnthe
selectorswitchtothe“off”position.
2. SetthetimedelayonunitNo.1to“3”minutes,andNo.2to“5”minutes.
3. Setthechangeoversettingoftheenthalpycontroltothe“d”setting(ComPac®IIA/Conly).
4. ProvidepowertoA/Cunitsandturndisconnectson.
5. Checkincomingpowertoeachunit.Forunitsdesignedforoperationon208/230v,60hzpower
supply,thetransformerisfactorywiredfora230powersupply.Fora208powersupplyremovethe
orangeleadfromthetransformerandconnecttheredlead.Insulatetheorangelead.
6. Cooling.UsetheSYSswitchtosetthethermostatto“AUTO”.Slowlylowerthecoolingtemperature
untiltheswitchcloses.Theindoorfanshouldoperateontheleadunit.Oncetheindoorfanturns
on,allowapproximately3to5minutesforthecompressortostart.Notethattheoutdoorfanmay
notcomeonimmediatelybecauseitiscycledbyrefrigerantpressures.Next,lowerthetemperature
untiltheswitchcloses.Followtheaboveproceduresforthelagunit.
 Thegreenlightontheleadlagcontrolshouldbeon.Oneamberlightwillbeontoidentifythelead
unit.Theotherlightshouldbeoff.Ifthelagunitcomesonwiththeleadunitthelightforthelag
unitwillnotcomeon.Youshouldneverhaveall3lightsonatonetime.
 Allowtheunitstorunfor2to3minutesthencheckthetemperaturedifferentialbetweenthereturn
airandthesupplyairwithdigitalthermometer.Thetemperaturedifferentialshouldbebetween12
and20degreesdependingonambienttemperature.
 Next,slowlyraisethecoolingtemperatureuntiltheswitchopens.Thecompressorandoutdoorfan
shouldturnoff.Theindoorfanwillcontinuetorunfor“90”secondsuntilthefanpurgetimesout.
Raisethetemperatureuntiltheswitchopens.Theleadunitwillshutdownaccordinglytothesame
proceduresasoutlinesabove.
 Note:(ComPac®IIA/Conly)Tocheckthesystemoperationunderdifferentambientconditions,
theairtemperatureandenthalpysensorsmustbe“tricked”.Whenoutdoorambientconditions
arehigherthanthecontrolsetting,acomponentcooleraerosolmaybesprayeddirectlyintothe
enthalpysensortostimulatelowenthalpyconditions,causingtheeconomizerdampertoopen.
 Alternately,whenoutdoorconditionsarelowerthanthesetpoint,asourceofheatsuchasahair
dryercanbedirectedontheenthalpysensortosimulatewarmconditions,whichwillbringon
mechanicalcoolingandstartthecompressor.
7.Heating.Slowlyraisetheheatingtemperatureuntiltheswitchcloses.Thefanandelectricalheat
shouldimmediatelycycleon.Theunitshouldstartblowingwarmairin2to3minutes.Next,raise
thetemperatureuntiltheswitchcloses.Followtheaboveproceduresforlagunit.
Holdthemanualadvancebuttoninforninesecondstheleadlaglightsshouldswitch.Next,slowly
lowerthetemperatureuntiltheswitchesopen.Thelagunitshouldshutdownimmediately.Next,
slowlylowerthetemperatureuntiltheswitchopens,theleadunitshouldshutdownimmediately.
8.Replacethermostatcoverandpanelsontheunit.

LL357D4 PDS, 4.2011 8
Mode of Operation
Foranunmannedsite,AutoMUSTbeselectedastheOperatingMode.Sincethecontrolmodulein
theLL357D4doesnothavea"G"input,thefanselectorswitchonthethermostatisnotfunctional.In
normaloperation,thefanandthecompressoroperatesimultaneously.Forcontinuousfanondualunit
installations,installajumperwirebetweenterminals8and3andremovethejumperwirebetween1
and3.Theseterminalsareonthelowvoltageterminalboardintheairconditionercontrolbox.
TherearefourpossibleoperatingmodesfortheLL357D4,Off,Cool,Heat,andCool&Heat(auto-
changeover).ModesareaccessedbypressingtheSYS(left)button.
OFF Mode
•Inthismode,thethermostatwillnotheatorcool.
Heat Mode
•Inthismode,thethermostatcontrolstheheatingsystem.Whentheheatison,the
flameiconappearsonthedisplay.
Cool Mode
•Inthismode,thethermostatcontrolsthecoolingsystem.Whenthetheunitis
cooling,thesnowflakeiconappearsonthedisplay.
Cool and Heat Mode (AutoChangeover)
•Inthismode,thethermostatcontrolsthecoolingandheatingsystems,
automaticallychangingoverfromonetotheotherasneeded.
•Thetimingdisplayalternateswiththesettemperatureevery10secondsinthecool
andheatmode.
Lockout Feature
Thethermostathasabuttonlockoutfeaturesothemodecannotbechangedandthe
temperatureadjustmentislimited.SelecttheappropriatelockoutfromConfiguration
ModeSettings.
ToactivatetheLOCKfeature:
1.SimultaneouslypresstheSYS,RIGHTandUPbuttonsfor10seconds.
2.Thelockouticonwilldisplayandthelockoutfunctionwillbeenabled.
TodeactivatetheLOCKfeature,repeatsteps1and2above.

LL357D4 PDS, 4.2011 9
Troubleshooting
Symptom Remedy
Nodisplay Checkfor24VACatthermostat;displayisblankwhen
24VACisnotpresent.
Indoorblowerdoesnotturnon Verifywiringiscorrect.ChecksettingsinConfigMode,
No.6,“Settings”.
Allthermostatbuttonsareinoperative. Verify24VACispresent;unitlocksoutwhen24VAC
notpresent.
Noresponsewhenfirstbuttonispressed. Firstbuttonpressedonlyactivatesbacklight.
AirconditionersturnsOnandOfftoofrequently
(shortcycles)
Increasetemperaturedifferential.SeeConfigMode,
steps2&3.
Statusindicatorlightdoesnotcomeonduring
callforCoolingorHeating.
Turnstatusindicatorlightfunctionon.SeeConfig
Mode,Step14.
Roomtemperatureisnotcorrect. Calibratethermostat.SeeConfigMode,step11.
Lockiconisdisplayedwhenanybuttonis
pressed.
Thermostathasthelockoutfunctionactivated.See
LockoutFeatureandConfigMode,step8.
ErondisplayinsteadofSEntemperature CheckforabadconnectionatS1andS2terminals.
SeeConfigMode,step12
Airconditionerisnotcoolingorheating. Verifywiringiscorrect.Gentlypulloneachwireto
verifythereisagoodconnectionattheterminalbloc.
Problemnotlistedabove PressResetonce.Timeanddayarereset;
configurationssettingsarenotchanged.

LL357D4 PDS, 4.2011 10
Configuration Mode
ToenterConfigurationmode:
1. VerifythatthethermostatisintheOFFmode.
2. PresstheSYS(left)buttonuntiltheoffmodedisplays.
3. Removethethermostatscoverbygentlypullingononecorneratthetopofthethermostat.
4. PresstheCONFIGbuttonfor1second.
5. Presstheupordownbuttontochangethesettingswithineachscreen.
6. PresstheRIGHTbuttontoadvancetothenextscreen.Presstheleftbuttontoreturntoprevious
Screen
Number Description
Marvair Recommended
Selection Default
1TemperatureScale°For°C Asdesired F
21stStageTemperatureDifferential1°Fto3°F(0.5°Cto1.5°C) 2°F 1°
32ndStageTemperatureDifferential1°Fto6°F(0.5°Cto3.0°C) 2°F 2°
4StagedOffOutputs
1=outputsstagedoffindependently
2=outputsstagedoffsimultaneously
Select111
5MinimumDeadband
2°Fto9°F(1.0°Cto4.5°C)
3°F 5°
6System
Choosefromheatpump,non-heatpump(airconditioner),reversingvalve
andnumberofcompressors.
Select“non-heatpump”and
“Electric”1
GAS
7AuxiliaryDelayOn
Setthetimedelay(inminutes)foraux.heattobelockedoutafteracallfor
secondstage
Setto0minutes.10:00
8Lockout
Selectthenumberofdegreesthatthesettemperaturecanbechanged
duringkeypadlockout.
Asdesired 00
9MaximumHeatingSetpoint
55°Fto90°F(13°Cto232.0°C)
Nohigherthan78°F(25.6°C) 90°
10 MinimumCoolingSetpoint
45°Fto75°F(7.0°Cto24.0°C)
Nolowerthan68°F(20°C) 45°
11 RoomTemperatureOffset
+9°Fto-9°F(+4.5°Cto-4.5°C)
Asdesired 0°
12 TemperatureSensor
1=Onboardtemperaturesensor
2=Onlyremotesensor
3=Avg.temperatureofon-boardsensorandremotesensor
Asdesired 1
13 CoolingfanDelayOffTime
0,30,60,90seconds
0seconds 0
14 Statusindicatorlight
0=statusindicatorneveron
1=statusindicatoronwithfirststage
2=statusindicatoronwithsecondstage
Select1 1
ToexittheConfigurationMode,presstheCONFIGswitchfor1second.
Note:Theredlightindicatestheunit(s)isintheheatingcycleandthegreenlightindicatethattheunit(s)isinthecoolingcycle.
1Settingsandselectionsinitalicsarerequiredsettings/selections.