Defrost Control - Danfoss EKC 414A Manual

Defrost
A defrost can be started in five ways: via the data communication, via a signal at the
DI input, via clock module and setting, via an internal timer function or by a pushon
the lower of the displays' control buttons. It is recommended to set the timer func-
tion even if one of the three first options is used. The timer function will then act as
safety period if the original defrost start should be overdue. The defrost itself can be
stopped based on time, or a temperature sensor can be placed on the evaporator so
that defrost can be stopped based on temperature value.
Defrost stop temperature
If a defrost sensor has been mounted on the evaporator, the defrost can be stopped
at a given temperature. The temperature value is set. If a defrost sensor has not been
mounted, the defrost will be stopped based on time.
Cf. d4 and d10.
Interval between defrost starts
It is recommended to start the defrost via the data communication or via a signal at
the DI input and then use this setting as precautionary measure if the normal defrost
signal should fail to appear (the time interval must be greater than the time between
two normal defrost starts).
But the interval function may also be used as a simple defrost start function where
the defrost is started periodically, say, every eight hours. If defrost is to be performed
at specific times of the day, the setting must be made accordingly. (The internal coun-
ter is zeroset after a power failure).
The time interval is reset at each defrost start.
Max. defrost duration
If you have chosen to stop defrost based on temperature, this setting will constitute a
safety period where the defrost will be stopped if no stop based on temperature has
taken place by then. If you have selected defrost stop based on time, this setting will
be the defrost time.
Time displacement of defrost cutins during start-up
The function is only relevant, if you have several refrigeration appliances or groups
where you would like the defrost to be displaced. This function is also only relevant if
you have selected defrost with interval start (d03).
The function delays the defrost by the set number of minutes, but for the very first
defrost it only does it when the controller has been energised.
Drip-off time
Here you set the time that is to elapse from the end of a defrost and until compressor
is to be resumed. (The time when water is dripping off the evaporator).
Fan start delay after defrost
Here you set the time that is to elapse from when the compressor is started after a
defrost and until the fan may resume operation. (The time where the water is "bound"
to the evaporator).
Fan start temperature
The fan may also be started a little earlier than mentioned under "Delayed fan start
after defrost" if the defrost sensor registers a permissible value. Here you can set the
value for when the fan may start.
Fan cut in during defrost
Here you set whether the fan is to operate during defrost.
If the ON function is selected, the settings in d07 and d08 are not relevant
Defrost sensor
Here you set whether the defrost sensor is to beS4, S5 or if there is not going to be a
defrost sensor at all.
0: S4 (S )
out
1: S5 (S )
def
2: No defrost sensor. Defrost stop is based on time.
Defrost at power up
Here you set whether the controller is to start with a defrost when power is supplied
to the controller during start-up or after a power failure. The function ensures that
defrost will be performed on weak networks with frequent power failures.
6 Manual RS8CK502 © Danfoss 05-2005

Defrost control

d02 Def. Stop Temp
d03 Def.Interval
d04 Max Def.time
d05 Time stagg.
d06 Drip Off time
d07 Fan Start Del.
d08 Fan Start Temp.
d09 Fan During Def.
d10 Def Stop Sensor
d13 Def. At Power Up
Def. start
Here you can start a manual defrost
Hold After Def.
Shows ON when the controller is
operating with coordinated defrost.
EKC 414A