D – 508 C – 07/02 D – EN pag. 24/36
Controller
The controller is installed as standard in every unit; it can be used to modify the setpoints of the unit and to
check control parameters. A display shows the machine's operating status, programming values and
setpoints (e.g. temperatures and pressures of fluids such as water and refrigerant). This control device
maximizes the DAIKIN chiller energy efficiency and reliability. It uses sophisticated software with predictive
logic to select the most energy-efficient combination of compressor, electronic expansion valve and
condenser fan to keep stable operating conditions and maximize energy efficiency. The compressors are
automatically used on a rotation basis to ensure even operating hours. The controller protects critical
components in response to external signals received from the system field sensors measuring: motor
temperatures, refrigerant gas and oil pressures, correct phase sequence and phase failure.
Control section - main features:
•
Management of the compressor capacity slide and the electronic expansion valve in accordance with
the distributed multiprocessor logic system
•
Chillers enabled to work in partial failure condition thanks to the distributed multiprocessor logic
system
•
Full operational routines for following conditions:
-
High ambient temperature
-
High thermal load
-
High evaporator inlet water temperature (start-up)
•
Display of evaporator inlet/outlet water temperature
•
Display of both condensing and evaporating temperatures and pressures, and both suction and
discharge superheat temperatures for each circuit
•
Regulation of cooled water outlet temperature. Temperature tolerance
±
0,1°C
•
Compressors and evaporator pump hour counters
•
Display of status of safety devices
•
Equalization of the number of running sessions and working hours of the different compressors
•
Excellent management of compressors load
•
Management of cooling tower fans according to condensing pressure
•
Automatic re-start in case of power supply interruption (adjustable)
•
Soft load
•
Return temperature reset
•
AOT Reset
•
Setpoint Reset
•
Demand limit or Current limit
•
Speedtrol control (optional)
Safety - each refrigerant circuit
High pressure (pressure switch)
Low pressure (pressure switch)
Compressor overload
Condenser fan magneto-thermal protection
High discharge temperature on the compressor
Phase monitor
Star / Delta transition failure
Low delta (differential) pressure between suction and discharge
Low pressure ratio
High oil pressure drop
Low oil pressure
