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Manual RS8DZ702 © Danfoss 03-2012 EKC 202 / 302
Start of defrost
A defrost can be started in different ways
Interval:
Defrost is started at fixed time intervals, say, every
eight hour
Refrigeration time:
Defrost is started at fixed refrigeration time inter-
vals, in other words, a low need for
refrigeration will ”postpone” the coming defrost
Contact
Defrost is started here with a pulse signal on a
digital input.
Manual:
An extra defrost can be activated from the control-
ler’s lower-most button
S5-temp.
In 1:1 systems the efficiency of the evaporator can
be followed. Icing-up will start a defrost.
Schedule
Defrost here can be started at fixed times of the
day and night. But max. six defrosts
Network
A defrost can be started via data communication
All the mentioned methods can be used at random – if just one
them is activated a defrost will be started. When the defrost starts
the defrost timers are set at zero
Digital input
The digital input can be used for the following functions:
- Door contact function with alarm if the door has been open for
too long.
- Defrost start
- Start/stop of regulation
- Change-over to night operation
- Case cleaning
- Change to another temperature reference
- Inject on/off
Case cleaning function
This function makes it easy to steer the refrigeration appliance
through a cleaning phase. Via three pushes on a switch you
change from one phase to the next phase.
The first push stops the refrigeration – the fans keep working
”Later”: The next push stops the fans
”Still later”: The next push restarts refrigeration
The different situations can be followed on the display.
There is no temperature monitoring during case cleaning.
On the network a cleaning alarm is transmitted to the system unit.
This alarm can be ”logged” so that proof of the sequence of events
is provided.
Defrost on demand
1 Based on refrigeration time
When the aggregate refrigeration time has passed a fixed time,
a defrost will be started.
2 Based on temperature
The controller will constantly follow the temperature at S5.
Between two defrosts the S5 temperature will become lower
the more the evaporator ices up (the compressor operates for a
longer time and pulls the S5 temperature further down). When
the temperature passes a set allowed variation the defrost will
be started.
This function can only be used in 1:1 systems
A pulse signal
starts the
defrost
-
+
+
°C
1
÷
+
Fan
2
÷
÷
Off
3
+
+
°C
If you need coordinated defrost, this must be done via data com
-
munication.