Danfoss AK-CC 750A User Manual page 33

Receive external on/off alarm signal
Receive external analog alarm signal
Product sensor with alarm function
Liquid injection
Control of AKV / stepper valves
Control of solenoid valves in liquid line
Superheat regulation wit P0 and S2 measurement
MOP control
Refrigerant choice
Defrost function
Electrical defrost
Warm Brine defrost, Hot gas defrost
Smelt function
Drip tray heat
Adaptive defrost
Defrost stop on temperature or time
Coordinated defrost via network
Miscellaneous
Dedicated alarm for refrigerant leak
Alarm priorities
Sensor correction
Option for connection of separate display
Separate thermostats
Separate pressostats
System signals via data communication
Signal for P0-optimasation
Night setback
Inject ON-signal (forced closing)
Light control
Coordinated defrost
Forced cooling
A bit more about the functions
Common thermostat
The thermostat temperature can be either a weighting of the S3
and S4 sensors in section A.
Alternatively, the thermostat temperature can be a minimum
value, a maximum value or an average value of all S3 or S4 sensors
for the refrigeration sections used.
Modulating thermostat
AKV / stepper:
The function can only be used on central plant.
The opening degree of the valve is adjusted so that an accurate,
constant temperature is maintained. .
Solenoid valve:
This function can be used on both central systems and on indirect
refrigeration appliances. The valve's duty cycle is adapted so that
optimum temperature regulation is achieved on the basis of a
specific time period. The valve's duty cycle is desynchronised so
that an even load is achieved across the entire system
Changeover between two thermostat references
The function is used for appliances where contents are frequently
changed and where a different thermostat reference is required.
Changeover between the two references can take place by means
of a switch function.
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RS8HP102 © Danfoss 2018-09
Day/night signal for raising the reference
The built-in week diagram can be used for raising the thermostat
reference, but it is also possible to use an external ON/OFF signal
or a signal via the network.
Product sensors
Each appliance section has a separate product sensor which can
be used for monitoring/registering the temperature.
Appliance cleaning function
A switch function with pulse pressure will activate the function
whereupon refrigeration will be stopped. The fans continue
operating.
"Later": Next push on the switch will stop the fans.
"Still later": Next push on the switch will restart refrigeration.
When a display is mounted at the appliance the various situations
may be followed by the readout:
Normal operation: Appliance temperature
1st push: Fan
2nd push: OFF
3rd push: Appliance temperature
Appliance shut down
Signal about shutdown can be received via data communication
or from a contact on a On/Off input.
Door switch function
In freezing and cold rooms the door switch is used for switching
the light on and off, for starting and stopping the refrigeration,
and for sounding the alarm if the door has been open for a long
time
Light function
The light function can be activated by the door switch, the inter-
nal time diagram or a signal via the network.
Defrost sensor S5
On long evaporators it may be necessary to mount two sensors in
order to ensure the correct defrost of the evaporator. The sensors
are for example named S5A-1 and S5A-2.
"Inject ON" override function
The function closes expansion valves on the evaporator control
when all compressors are stopped.
The function can take place via the data communication, or it may
be wired via a relay output.
Adaptive defrost
The function requires signals from S3 and S4 as well as from
condensing pressure Pc. The expansion valve must furthermore
be type AKV.
The function cannot be used in combination with pulsation of
fans.
If you want to know more about the functions, go to
chapter 5.
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