Danfoss AK-CC 550 User Manual

8 Manual RS8EN502 © Danfoss 02-2010 AK-CC 550
Control of two compressors
Thetwocompressorsmustbeofthesamesize.Whenthecontrol-
lerdemandsrefrigerationitwillrstcutinthecompressorwith
the shortest operating time. After the time delay the second
compressor will be cut in.
Whenthetemperaturehasdroppedto”themiddleofthedieren-
tial”,thecompressorwiththelongestoperationtimewillbecut
out.
The running compressor will continue until the temperature has
reachedthecutoutvalue.Thenitwillcutout.Whenthetempera-
tureagainreachesthemiddleofthedierential,acompressorwill
again be started.
Ifonecompressorcannotmaintainthetemperaturewithinthe
dierential,thesecondcompressorwillalsobestarted.
Ifoneofthecompressorshasrunonitsownfortwohours,the
compressorswillbechangedoversothatoperationaltimeisbal-
anced.
The two compressors must be of a type that can start up against a
high pressure.
Thecompressors’ssettingsfor”MinOntime”and”MinOtime”
willalwayshavetoppriorityduringnormalregulation.Butifone
oftheoverridefunctionsisactivated,the”MinOntime”willbe
disregarded.
Railheat
Itispossibletopulse-controlthepowertotherailheatinorderto
saveenergy.Pulsecontrolcaneitherbecontrolledaccordingto
day/nightloadordewpoint.
Pulse control according to day and night
VariousONperiodscanbesetfordayandnightoperation.
A period time is set as well as the percentage part of the period in
whichtherailheatisON.
Pulse control according to dew point
InordertousethisfunctionasystemmanagerofthetypeAK-SM
is required which can measure dew point and distribute the cur-
rentdewpointtotheappliancecontrollers.Forthistherailheat’s
ONperiodiscontrolledfromthecurrentdewpoint.
Twodewpointvaluesaresetintheappliancecontrol:
•Onewheretheeectmustbemax.i.e.100%.(o87)
•Onewheretheeectmustbemin.(o86).
Atadewpointwhichisequaltoorlowerthanthevaluein086,
theeectwillbethevalueindicatedino88.
Intheareabetweenthetwodewpointvaluesthecontrollerwill
manage the power to be supplied to the rail heat.
During defrosting
Duringdefrostingtherailheatwillalwaysbe100%ON.
Dew point
Rail heat

Danfoss AK-CC 550 Specifications

General

Brand	Danfoss
Model	AK-CC 550
Category	Controller
Language	English