Defrost Control - Danfoss AK-CC55 User Manual

AK-CC55 Single Coil and Single Coil UI

Defrost control

Table 33: Defrost control
Function Description
Control state A Readout of the actual control state of the controller
Defrost sensor tem- Actual temperature of selected defrost stop sensor
perature A
S5 Evaporator A Actual sensor value
S5 Evaporator B Actual sensor value
Defrost A Actual status of output function
Defrost B Actual status of output function
Defrost time A Read the duration of the ongoing defrost or the dura-
tion of the last completed defrost.
Adaptive defrost Actual state of the adaptive defrost function
state
Accumulated de- Number of defrosts carried out since the initial pow-
frosts er-up or since the resetting of the function
Accumulated skip- Number of defrosts skipped since the initial power-up
ped defrosts or since the resetting of the function
Tc average temp. Average value of the condensing temperature signal
distributed via the system manager to the case con-
trollers that are using adaptive defrost. At transcritical
CO2 sites the receiver pressure is distributed to the
case controllers. The function needs to be set up in
the system manager.
Start defrost Command for starting a defrost
Stop defrost Command for stopping an ongoing defrost cycle
Defrost method Select method of defrost
Defrost stop method Here you define whether a defrost cycle is to be stop-
ped by time or by a temperature sensor
Defrost stop limit A When the selected defrost stop sensor reaches the set
limit, the defrost cycle is terminated
Max. defrost time Max duration of a defrost cycle. The setting is also
used as a safety time if the defrost is stopped on tem-
perature. If the selected defrost stop sensor does not
reach the set defrost stop temperature limit within
the set time, the defrost will be stopped anyway.
Defrost start interval The function is zeroset and will start the timer func-
tion at each defrost start. When the time has expired
the function will start a defrost. The function is used
as a simple defrost start, or it may be used as a safe-
guard if the normal signal fails to appear. If master/
slave defrost without clock function or without data
communication is used, the interval time will be used
as max. time between defrosts. If a defrost start via
data communcation does not take place, the interval
time will be used as max. time between de-
frosts.When there is defrost with clock function or da-
ta communication, the interval time must be set for a
somewhat longer period of time than the planned
one. In connection with power failure the interval
time will be maintained, and when the power returns
the interval time will continue from the maintained
value. he interval time is not active when set to 0
© Danfoss | Climate Solutions | 2021.02
Values
0=Normal ctrl., 1=Hold after defrost, 2=Min ON timer,
3=Min OFF timer, 4=Drip off, 10=Main switch OFF,
11=Thermostat cut-out, 12=Frost protection S4,
13=Not_used, 14=Defrost, 15=Fan delay, 17=Door
open, 18=Melt period, 19=Modulating temp. control,
20=Emergency control, 23=Adaptive superheat con-
trol, 24=Start injection, 25=Manual control, 26=No re-
frigerant selected, 16=Forced closing, 29=Case clean-
ing, 30=Forced cooling, 31=Door open, 32=Power-up
delay, 33=Air heating, 45=Shut down controller,
48=Adaptive liquid control
0=OFF, 1=ON
0=OFF, 1=ON
0=OFF, 1=Error, 2=Tuning, 3=OK, 4=Little ice, 5=Medi-
um ice, 6=Heavy ice
0=OFF, 1=ON
0=OFF, 1=ON
0=None, 1=Electrical, 2=Hot gas, 4=Air/Offcycle
0=Time, 1=S5 sensor, 2=S4 sensor, 3=S5A and S5B
Code Short name
u00 u00 Ctrl. state
U73 U73 Def.StopTemp
u09 u09 S5 temp.
u75 u75 S5 temp. B
u60 u60 Def. relay
u83 u83 Def. relay B
u11 u11 Defrost time
U01 U01 AD state
U10 U10 Acc.defrost
U11 U11 Acc.def.skip
x02 --- Tc temp. Ave
x09 --- Def. Start
x10 --- Def. Stop
d01 d01 Def. method
d10 d10 DefStopSens.
d02 d02 Def.StopTemp
d04 d04 Max Def.time
d03 d03 Def.Interval
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