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Manual RS8DZ702 © Danfoss 03-2012 EKC 202 / 302
Defrost
Defrost control
The controller contains a timer function that is zeroset after each defrost start.
The timer function will start a defrost if/when the interval time is passed.
The timer function starts when voltage is connected to the controller, but it is displaced the first
time by the setting in d05.
If there is power failure the timer value will be saved and continue from here when the power
returns.
This timer function can be used as a simple way of starting defrosts, but it will always act as
safety defrost if one of the subsequent defrost starts is not received.
The controller also contains a real-time clock. By means of settings of this clock and times for the
required defrost times, defrost can be started at fixed times of the day. If there is a risk of power
failure for periods longer than four hours, a battery module should be mounted in the controller.
(only possible in EKC 202)
Defrost start can also be accomplished via data communication, via contact signals or manual
start-up.
All starting methods will function in the controller. The different functions have to be set, so that
defrosts do not ”come tumbling” one after the other.
Defrost can be accomplished with electricity, hot gas or brine.
The actual defrost will be stopped based on time or temperature with a signal from a tempera
-
ture sensor.
Defrost method
Here you set whether defrost is to be accomplished with electricity or "non".
During defrost the defrost relay will be cut in.
When gas defrosting the compressor relay will be cut in during defrost.
d01
Def. method
Defrost stop temperature
The defrost is stopped at a given temperature which is measured with a sensor (the sensor is
defined in d10).
The temperature value is set.
d02
Def. Stop Temp
Interval between defrost starts
The function is zeroset and will start the timer function 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 safeguard if the normal
signal fails to appear.
If master/slave defrost without clock function or without data communication is used, the inter
-
val time will be used as max. time between defrosts.
If a defrost start via data communication does not take place, the interval time will be used as
max. time between defrosts.
When there is defrost with clock function or data communication, the interval time must be set
for a somewhat longer period of time than the planned one, as the interval time will otherwise
start a defrost which a little later will be followed by 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.
The interval time is not active when set to 0.
d03
Def Interval
(0=off)
Max. defrost duration
This setting is a safety time so that the defrost will be stopped if there has not already been a
stop based on temperature or via coordinated defrost.
(The setting will be the defrost time if d10 is selected to be 0)
d04
Max Def. time
Time staggering for defrost cut ins during start-up
The function is only relevant if you have several refrigeration appliances or groups where you
want the defrost to be staggered in relation to one another. The function is furthermore only
relevant if you have chosen defrost with interval start (d03).
The function delays the interval time d03 by the set number of minutes, but it only does it once,
and this at the very first defrost taking place when voltage is connected to the controller.
The function will be active after each and every power failure.
d05
Time Stagg.
Drip-off time
Here you set the time that is to elapse from a defrost and until the compressor is to start again.
(The time when water drips off the evaporator).
d06
DripOff time
Delay of fan start after defrost
Here you set the time that is to elapse from compressor start after a defrost and until the fan
may start again. (The time when water is “tied” to the evaporator).
d07
FanStartDel
Fan start temperature
The fan may also be started a little earlier than mentioned under “Delay of fan start after defrost”,
if the defrost sensor S5 registers another allowable value than the one set here.
d08
FanStartTemp
Fan cut in during defrost
Here you can set whether fan is to operate during defrost.
0: Stopped (Runs during pump down)
1: Running (stopped during "fan delay")
2: Running during pump down and defrost. After that stopped
d09
FanDuringDef
Defrost sensor
Here you define the defrost sensor.
0: None, defrost is based on time
1: S5
2: Sair
d10
DefStopSens.