Technical data

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V
Precision Air Conditioning
Precision Air Conditioning
8
Technical Manual : 6258867 F 07/2012
General Description
STANDARD FEATURES
Electrical
The control panel contains the necessary fan motor contactors and overloads,
compressor starter (X type units) contactors, transformer, sub circuit protection, volt free
contacts, mains and inter-connecting terminals. The panel is situated within the cabinet
and is hinged for easy access to other components within the unit. The electrical control
panels are wired to the latest European standards and codes of practice.
Main Electric Isolator
To ensure complete unit isolation of the electrical panel during adjustment and
maintenance a door interlocking isolator is provided as standard.
Units are fitted with the microprocessor controller which offers powerful
analogue and digital control to meet a wide range of monitoring and control features
including a real time clock and a communication port plus networking and
BMS connections.
A 4 x 20 character backlit LCD door mounted display keypad assembly is used to view
the unit status and allow operator adjustment.
Controls
For further details, please refer to the Controls section.
Head Pressure Control -
Stand Alone
Refer to the Outdoor Unit section, General Description.
OPTIONAL EXTRAS - ENERGY SAVING
Electronic Expansion
Valves (EEV)
(A & X Models)
Electronic expansion valves differ to the normal thermostatic expansion valves in their
ability to maintain control of the suction superheat at reduced head pressures. This can
lead to significant energy savings particularly at reduced loading and low ambient
temperatures.
EEV step position, superheat setpoint, head pressure set point and other features can be
viewed and adjusted via the microprocessor display keypad.
Factory fitted, for full details refer to Design Features & Information.
CAUTION
As standard, the Intelligent Head Pressure Control option is included when the EEV
option is selected.
As an alternative to the stand alone head pressure control fitted to the outdoor
condensing unit or condenser, the system can be fitted with a voltage regulating fan
speed controller which allows set point adjustment and system monitoring via the indoor
unit microprocessor controller.
A pressure transducer is fitted to the liquid line which in turn feeds back the head
pressure to the microprocessor. The condenser fan speed can then modulate via the
controller to provide optimum control under varying ambient conditions. The head
pressure can be monitored via the display keypad.
Head Pressure Control -
Intelligent
(A & X Models)
With the head pressure factory set to 14 Barg (203 psig) part load, EER values are
significantly improved, which in turn lowers energy consumption.
GENERAL