Haier 1U09ES2VHA Service Manual - page 30
SEQUENCE OF OPERATION
PAGE 30
ENGLISH
ambientandtube,provideinformationtotheoutdoorcontrol
boardtomonitorthesystemandregulatethefrequencyof
thecompressor,EEVpositioning,andoutdoorfanspeedto
achievethedesiredroomtemperature.
Whenheatinghasbeensatisfied,theoutdoorunitcompres-
sorwillturnofffirstandfollowedbytheoutdoorfan.The
4-wayvalvewillde-energize2minutesaftercompressor
stops.
Theindoorunitfanwillcontinuetorunatminimumspeedun-
tilindoorcoiltemperaturereachesaminimumtemperature
anditwillturnoff.
Ifthesystemdetectsamalfunction,itmayshutdownor
showanerrorcodeontheindoorunitdisplayboardand/or
outdoorunitmainboardLED.
Defrost
Whenthesysteminitiatesacallfordefrost,theindoorfan
motorstops.Theindoorunitdisplaywillnotchange.Any
indoorunitmalfunctionswillbeignoredatthistime.Thesys-
temwillcyclethroughthedefrostoperation.Anyindoorunit
malfunctionswillbeignoreduntilthecompressorrestarts
andhasbeenoperatingfor30seconds.Attheconclusionof
thedefrostcycle,theindoorfanwillenterthecoldairproof
operation.Heatmoderesumes.
Automatic Heating Temperature Compensation
Whenthesystementersheatingmode,atemperaturecom-
pensationadjustmentisaddedtotheoperatingparameter.
Thisadjustmentiscanceledwhenexitingheatmode.
Indoor unit
Toentertheheatmode,pointtheinfraredremotecontroller
attheindoorunitandpressthepowerbutton,thenpressthe
HEATmodebuttonifnotalreadysettoheatmode.
Thesignalsreceivedbytheinfraredreceiverarerelayedto
themainboardoftheindoorunittoturnthesystemonand
set it to heat mode.
Theindoorunitmainboardwillactivatethedisplayofthe
indoorunit,illuminatingthedisplay,indicatingtheroomtem-
peratureandcurrentstatusoftheunit.
Theindoorunitmainboardwillsignalthelouversteppermo-
tortoopenthelouvertoastationaryposition.
Theindoorunitmainboardwillpoweruptheindoorfanmotor
after the outdoor unit has started and heating of the indoor
coilhastakenplace(seecoldairproofoperation).Theindoor
fanmotorhasafeedbackcircuitwhichprovidestheindoor
unitmainboardwithinformationforcontrollingthespeedof
the fan motor.
Temperature sensors
Theindoorunithastwosensorsthatprovidetemperature
informationtotheindoorunitmainboard.Thesensors:an
indoorambienttemperaturesensor,andpipetemperature
sensor,areusedforcontrollingthesystemduringheatmode.
Theresistancevaluesofthesensorswillvarywithtempera-
ture.Theresistancetotemperaturevaluescanbefound
usingatemperature/resistancechartspecifictothesensor
being checked.
Communication
Theindoorandoutdoorunitmainboardscommunicateviaa
digitalsignalonthewireconnectedtoterminal3ofeachunit.
Aspliceorbreakinthiswirewillcauseacommunicationerror.
Whenacommandisreceivedfromtheremotecontrol,the
indoorunitmainboardcommunicateswiththeoutdoorunit
mainboardviatheterminal3wiretoperformtherequested
function.
Outdoor unit
Uponarequestforheat,theoutdoorunitmainboardapplies
powertothe4-wayvalve,outdoorfanmotorandcompres-
sor.Dependingonsystemcycling,theremaybeuptoa3
minutewaitperiodbeforethecompressorandoutdoorfan
start.)
NOTE:Donotmeasurecompressorvoltages,damagetothe
metermayresult.
Iftheambientroomtemperatureisabovethesettempera-
ture,yetlowerthan2°Fabovethesettemperature,the
systemwilladjusttherunningfrequencyofthecompressor
automaticallyaccordingtochangesinambienttemperature.
Theoutdoorunitmainboardalsocontrolsthepositionofthe
EEV(ElectronicExpansionValve)
toregulatetheflowofrefrigeranttotheindoorunitevapora-
tor coil.
Temperature sensors
Fourtemperaturesensorslocatedintheoutdoorunitprovide
temperatureinformationtotheoutdoorunitmainboardfor
controlofthesystemduringheatmode.
Theoutdoorambienttemperaturesensorprovidesthe
temperatureoftheairdrawnintothecondensercoilofthe
outdoor unit.
Thedefrosttemperaturesensorprovidesthetemperature
sensedattheoutputofthecondensercoil.
Thesuctionlinetemperaturesensorprovidesthetempera-
turesensedattheincomingsuctionlinepipe.