TECHNICAL MANUAL
Chapter 6 - Versions available
NGSi 05÷15
8
ENGLISH
EN
The data in this manual are not binding and they can be modified by the manufacturer without notice. Reproduction of this manual is strictly prohibited
5.7 Control panel
The control panel is constructed in compliance with the relevant European standards. The panel is accessed by removing the front and side
panels and top of the unit with the aid of a suitable tool. The panel control protection rating is IP24. The panel also comprises a terminal
board with clean contacts for remote ON-OFF switching, summer/winter switching, the auxiliary heater, the domestic hot water sensor,
control of a remote 3-way valve and contacts for the remote control panel and double set point operation.
5.8 Control system
All NGSi units are equipped with a microprocessor with overheating control by means of the electronic thermostatic valve operated in
response to the signals sent by the pressure transducers. The CPU also controls the water temperature setting, antifreeze protection,
compressor timing, alarm reset, alarm control and operating LEDs. On request, the microprocessors can be connected to BMS remote control
systems and the simpler HNS system with our terminals. The control system, combined with the use of INVERTERS and the on-board
sensors, monitors performance of the inverter compressor, circulator and fan (2 fans in 10 and 15 models) and adapts its constantly and
swiftly as required.
The INVERTER system reduces the system’s minimum water content from the conventional 12-15 litres/kW of chilling power to the
ABSOLUTE figures of 18 litres for the 05, 25 litres for the 07, 35 litres for the 10 and 45 litres for the 15 model in the NGSi series.
Thanks to these exceptionally low water contents, NGSI series units are suitable for systems without water tanks, with obvious
benefits in terms of reduction in unit size, installation space requirements, heat loss and system installation and maintenance costs.
5.9 Monitoring and protection devices
All units are supplied as standard with the following monitoring and protection devices: return water temperature probe on the system water
return line, operating and antifreeze probe on the pipe delivering water to the system, high pressure transducer, low pressure
transducer, compressor inlet and outlet temperature probes, compressor thermal protection devices, fan thermal protection devices, water
side flow switch to protect the evaporator and high pressure switch.
5.10 Water circuit
NGSi chiller units have an integral water circuit including the circulator pump, suitable for the use of chilled water and directly controlled by
the unit’s own control unit. The circulator, always of modulating type, has an induction motor. The water circuit also includes the expansion
vessel, the safety valve (6 bar) and the automatic air bleeder valve.
5.11 Fan speed regulation
The fan speed is controlled by the microprocessor in order to optimise the evaporation/condensation pressure for summer/winter operation,
to enable the unit to operate correctly.
CHAPTER 6
VERSIONS AVAILABLE
NGSi - reversible heat pump with integrated hydronic system (expansion vessel, safety valve, pressure gauge, modulating circulator pump,
flow switch, automatic air bleeder valve. intake/discharge valve).
Models available: 05, 07, 10 and 15.
6.1 Optional accessories
Hi-T - Multi-function touch screen remote control that integrates the centralized management of the minichiller and of the HNS system, the
functions of USB port, humidity and temperature sensors. It is also equipped with an extremely intuitive interface that simplifies the use of
the control.
CRH - Remote control panel for installation in the room for remote control of the unit, with extra functions in addition to those provided on
the unit, also able to control our hydronic terminals.
AG - Rubber dampers for installation underneath the unit to cushion any vibrations.
AK - Antifreeze kit (this accessory must be installed in the factory and must be specified when ordering). It comprises a heating cable wound
around the base of the unit near to the condensation coil and a Mylar heating element on the faces of the plate heat exchanger.
KDS - Double setpoint kit (already integrated in the Hi-T) for the management of a second working setpoint on the system side.
CHAPTER 7
INSTALLATION
7.1 General
When installing or servicing the unit, staff must comply strictly with the instructions provided in this manual and those on the unit itself, and
always take all necessary precautions. Failure to follow instructions may be dangerous.
MTA must be notified of the damage within 8 days. The Customer must draw up a written report in the event of significant damage.
WARNING:
The INVERTER control system is able to manage minimum system water contents of 18 litres for the 05 model, 25 litres for
the 07 model, 35 litres for the 10 model and 45 litres for the 15 model. These figures in litres are absolute values, and not values
per kW of rated power.
WARNING:
All the operations described below must only be performed by QUALIFIED STAFF. Before doing any work on the unit,
make sure that the electricity supply is disconnected.
On receipt of the unit, inspect it for damage: it left the factory in perfect condition. Any damage must be reported to the
forwarder at once and noted on the Delivery Sheet before it is signed.
