Specifications
RK0YG302 © Danfoss 04/2007 7
Brief outline about some of the controls
EKC 331T controller is used for capacity regulation of compres-
sors or condensers in compact refrigerating systems monitoring
minimum and maximum pressure. Regulation can be carried out
with up to 4 identical capacity steps. Step control with EKC 331T
reduces number of cut in/cut out cycles using patented smart
neutral zone control of the compressor. Using optional LON mod-
ule, EKC 331T can be integrated into ADAP-KOOL® system.
AK-PC 530 controller is used for capacity regulation of compres-
sors or condensers in refrigerating systems where compressor and
condenser control is based on a pressure transmitter or tempera-
ture sensor. There are eight outputs for control up to 8 compres-
sors and/or 8 fans. More fan outputs can be added via the connec-
tion of one or two EKC 331T as slave modules (up to 8 fan steps).
This analogue output can also be used for an external AKD speed
drive to control all condensers. Setup of controller is very user-
friendly by selection of a pre-dened compressor conguration.
Controller series AKC 25H_ is a complete control unit for capacity
regulation of compressors and condensers in small refrigerating
systems ensuring precise and stable refrigeration plant suction
and condensing pressure regulation. Being a part of ADAP-KOOL®
Refrigeration control systems, the compressor control ensures
optimum monitoring and alarm procedures and the possibility
of dierent monitoring functions to optimise refrigeration plant
operation.
AK-PC 840 controller is used for capacity control of complete
power pack in medium to big refrigeration systems. The modular
design with AK extension modules allows up to 12 compressors
with 3 unloaders, and up to 12 condenser fans. The controller of-
fers universal thermostats, pressostats, alarm inputs and analogue
inputs, based on already available measurements or extra inputs.
This functionality minimises the use of extra external equipment.
Comparison of controls in this section
Function Compressor and Condenser Cascade Chiller Dry cooler
Type EKC 331T AK-PC 530 AKC 25H1 AKC 25H3 AKC 25H5 AK-PC 840 AK-PC 730 AK-CH 650 AK-PC 420
Number of outlets 5 10 11 11 11 Basis 8 Basis 8 Basis 8 10
Expansion of number of
outlets
2x EKC 331T Up to 40 Up to 40 Up to 40
Total number of inputs and
outlets
8 33 + 8 27 34 32 Up to 80 Up to 40 30
Max. number of compressors 4 8 9 9 9 12 4
Compressor control Step Step Step Step Step/Speed Step/Speed Step/Speed Step/Speed
Control NZNZNZNZ PI PI PI PI
Control sensor, compressor Pressure/
Temperature
Pressure/
Temperature
Pressure Pressure Pressure Pressure/
Temperature
Temperature
Safety signal per compressor 1 Up to 6
via AKC 22H
Up to 6
via AKC 22H
Up to 6
via AKC 22H
Up to 6 Up to 6 Up to 6
Night setback XXXXXXXX
P0 - optimisation X X X X X X X
Load shedding X XX XX X
Three-way valve control X
Pump control XX
Max. number of fans 4 8 9 9 9 12 6 6
Fan control Step Step/Speed Step/Speed Step/Speed Step/Speed Step/Speed
PI/P control NZ P/PI NZ PI PI P/PI P/PI PI P/PI
Control sensor,
condenser
Pressure/
Temperature
Pressure/
Temperature
Pressure Pressure Pressure Pressure/
Temperature
Pressure/
Temperature
Pressure/
Temperature
Pressure/
Temperature
Floating condenser pressure X X X X X X X
Heat recovery function X X X X X X X
Condenser error monitoring X X X
Display Yes Option Option Option Option Option
Data communication Option Option DANBUSS LON RS 485 LON RS 485 LON RS 485 Option
General alarm input 5 Max. 10 Max. 10 Max. 10 3
General thermostat Max. 5 Max. 5 Max. 5
General pressure switch Max. 5 Max. 5 Max. 5
General analogue input Max. 5 Max. 5 Max. 5
Expanded water cooling control
Function AKC 25H7
Capacity control of brine system X
Capacity control
Fluid injection in the suction pipe
Function EKC 319
Limiting the discharge gas temperature X
Note
Adjustable speed is not available
on all compressors.
Check compressor data.
A list of AKC controls can be
found at the back of the cata-
logue.