Hussmann RDI-27 Installation & Operation Manual page 39

Time delay for couplings of two compressors
Settings indicate the time that has to elapse from the rst relay cuts in and until the
next relay has to cut in.
Reversed relay function for D01
0: Normal function where the relay cuts in when refrigeration is demanded
1: Reversed function where the relay cuts out when refrigeration is demanded (this
wiring produces the result that there will be refrigeration if the supply voltage to the
controller fails).
The LED on the controller's front will show whether refrigeration is in progress.
Defrost
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 dis-
placed the rst 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 xed 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.
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 di erent functions have to be
set, so that defrosts do not "come tumbling" one after the other.
Defrost can be accomplished with electricity, hotgas or brine.
The actual defrost will be stopped based on time or temperature with a signal from a
temperature sensor.
Defrost method
Here you set whether defrost is to be accomplished with electricity, gas, brine or
"non".
During defrost the defrost relay will be cut in.
(With brine the "refrigeration control valve" will be kept open during defrost)
Defrost stop temperature
The defrost is stopped at a given temperature which is measured with a sensor (the
sensor is de ned in d10).
The temperature value is set.
Interval between defrost starts
The function is zero set 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 interval 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.
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.
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 rst defrost taking place when voltage is connected
to the controller.
The function will be active after each and every power failure.
10 Manual RS8EP502 © Danfoss
c05 Step delay
c30 Cmp relay NC
Comp Relay
Here you can read the status of the
compressor relay, or you can force-
control the relay in the "Manual
control" mode
Defrost control
d01 Def. method
0 = non
1 = El
2 = Gas
3= Brine
d02 Def. Stop Temp
d03 Def Interval
(0=o )
d04 Max Def. time
d05 Time Stagg.
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