Specifications

26 RK0YG302 © Danfoss 05/2007

Application

AK-CH 650 is for capacity control of chillers.

The controller can control compressors, fans, pumps, defrosting

sequences and start/stop injection in a heat exchanger.

(If complete dry refrigeration control is required including a three-

way valve for the condenser, AK-PC 420 is recommended.)

Advantages

• Optimisation of charge temperature from the refrigeration area

which is used most

• Optimisation of condenser in relation to ambient temperature

• Flexible hardware platform with extension modules

• Fast set-up using pre-dened set-ups.

Control

• Compressor capacity is controlled via the charge temperature

S4. The reference can either be over-ridden via day/night signal,

an external 0-10 V signal, temperature signal or optimised auto-

matically from the refrigeration area which is used most

• Fan capacity is controlled either via the condensing pressure Pc

or a media temperature S7 (dry refrigeration). The reference can

be optimised via ambient temperature and changed during heat

recovery.

• The Ss and Sd sensors are used for monitoring of overheating of

the suction pipe and pressure pipe temperature respectively.

Additional functions

• Control of up to 6 compressors

• Compressors of the same or dierent size

• Speed control of one or two compressors

• Equalising of operating time between compressors

• Anti-cycle timers for each compressor

• Up to 6 safety inputs per compressor

• Capacity limit of compressors via 2 digital inputs

• Step or speed control of up to 8 fans

• Monitoring of fans

• Signal for start/stop of injection in heat exchangers

• Control and monitoring of 2 twin pumps. Automatic rotation

• Defrost control according to internal schedule, digital input or

network signal

• Defrost stop according to temperature and/or time

• Alarm monitoring of low suction pressure P0 (frost protection),

high condensing pressure and high brine temperature.

• Monitoring of external frost protection

• 5 digital inputs for alarm monitoring

• 5 thermostats and pressure switches for monitoring/control

• 5 voltage inputs 0-10 V d.c. for signal monitoring

AK-CH 650