The function must be used in connection with the compressor’s safety circuit, so that there will be no injection of
liquid into the evaporator when the compressor is stopped by the safety controls and cannot start again (however
not at low pressure – LP).
Via a setting (see o90 Fan at forced closing) it is possible to define whether the fan should be ON or OFF during
forced closing and whether an ongoing defrost is suppressed (i.e. put in standby position for a period of upto 10
minutes before it is cancelled) - this feature can be used in CO
2
systems to eliminate excessive heating while
compressors cannot run.
The signal can be received from the DI-input or via the data communication.
Door contact
The door contact function can via the digital inputs be defined for two different applications:
Alarm monitoring:
The controller monitors the door contact and delivers an alarm message if the door has been opened for a longer
period than the set alarm delay.
Alarm monitoring and stop of refrigeration:
When the door is opened, the refrigeration is stopped, i.e. the injection, the compressor and the fan are stopped and
light switches on. If the door remains open for a longer time than the set restart time, refrigeration will be resumed.
This will ensure that refrigeration is maintained even if the door is left open or if the door contact should be
defective. If the door remains open for a longer period than the set alarm delay, an alarm will also be triggered.
Alarm monitoring and stop of fans:
When the door is opened, only the fans are stopped. If the door remains open for a longer time than the set alarm
delay, an alarm is triggered and the fans will start running again.
Display
The controller has one plug for an external display.
One of the following display types can be connected:
• AK-UI55 Info (temperature display).
• AK-UI55 Set (temperature display and operation).
• AK-UI55 Bluetooth (temperature display and app interface).
The connection between the display and the controller must be made using an AK-UI55 cable.
The distance between the controller and the display must not exceed 100 m.
Figure 25: Controller with one display
Danf
oss
84B8235
Override
The controller contains a number of override functions which can be used together with Master Control functions in
the Danfoss gateway/system manager:
Table 6: Override functionality
Master control function
Description
MC Ther. toggle
Master control signal used for switching case load ON/OFF depending on the load condition
MC Load request
Master control signal used to control the load balance between multiple case controllers on the same suction line
MC Max. Te offset
Requested offset to actual evaporating temperature in order to keep the air temperature at the actual setpoint
MC Liquid control
Master control signal allowing switch to adaptive liquid control
AK-CC55 Compact
© Danfoss | Climate Solutions | 2022.08
BC365212986197en-000201 | 22