Specifications

18 RK0YG302 © Danfoss 05/2007

AK-PC 840

Application

AK-PC 840 is a complete regulating unit for capacity control of

compressors and condensers in commercial refrigeration.

In addition to capacity control the controller can give signals to

other controllers about the operating condition, e.g. forced clo-

sing of expansion valves, alarm signals and alarm messages.

Advantages

• Control of up to 12 compressors, which can have up to three

unloaders each

• Speed control of two compressors

• Suction pressure optimisation via data communication

• It can handle dierent compressor sizes

• Control of up to 12 fans

• Speed control of fans

• PI control

• Error detection of dirty condenser

• Separate functions independent of control

Control

The controller’s main function is to control compressors and con-

densers so that operation all the time takes place at the energy-

optimum pressure conditions. Both suction pressure and conden-

sing pressure are controlled by signals from pressure transmitters

transmitting a voltage signal, e.g. types AKS 32 and AKS 32R.

Functions

• Monitoring of safety automation can be connected.

•

When the compressors stop when there is an error in the system,

a signal can be given to other controls so that the electronic

expansion valves are closed.

• Alarm signals can be generated directly from the controller and

via data communication.

• Alarms are shown with texts so that the cause of the alarm is

easy to see.

• Liquid injection into suction line

• The status of the outputs and inputs is shown by means of light-

emitting diodes on the front panel

• Plus some completely separate functions thar are totally inde-

pendent of the regulation – such as alarm, thermostat and pres-

sure control functions.

Single compressor control

Single condenser control

Both compressor and condenser control