EN
i-ACCURATE i-AX - i-AW - i-AD - i-AT - i-AF
7
i-AF - water cooled
i-AD - air cooled
FREECOOLING UNITS – VERSION i-AF
The i-AF series units, in favourable outside conditions, can use the
cooling water to maintain the set environmental conditions with-
out the need for mechanical cooling using the compressor, or to
reduce the cooling load.
The i-AF series units use water as the cooling fluid, therefore
each refrigerant circuit is combined with a plate heat exchanger
installed on the unit, suitably sized to ensure minimum water side
pressure drop and consequently reduce power consumption of
the water pump.
The i-AF units are fitted as standard with EC radial fans in the
standard version.
Water-cooled condenser
Each unit is fitted with one (single-circuit units) or two (two-cir-
cuit units) braze welded stainless steel plate condensers.
Each refrigerant circuit features an automatic bypass valve to con-
trol minimum condensing pressure during operation in FC mode.
The units generally work in closed circuits, with outdoor dry
coolers, cooled by the outside air.
To avoid ice formation, it’s recommended to always use a glycol
mixture as the fluid inside the closed circuit, in the percentages
described in this manual based on the average minimum tempera-
ture reached in the installation site in winter.
The BDC (axial-flow fans with asynchronous motor) and i-BDC
Dry Coolers (axial-flow fans with EC motor) are supplied as stan-
dard accessories.
The antifreeze and fluid circulating pump are generally supplied by
other manufacturers.
For “open” circuits mechanical filters must be used to trap impu-
rities and prevent blockage of the braze-welded plate heat
exchanger.
To reduce energy consumption (pump), it’s suggested to use a
valve to close the circuit when the indoor unit is off.
Water circuit
The unit is fitted with a modulating 3-way valve to control the
flow of cooling fluid to the indoor heat exchanger for freecooling.
The opening and closing signal is generated and managed com-
pletely by the electronic controller on the air-conditioner so as to
maintain the desired conditions and ensure maximum energy sav-
ings.
DUAL FLUID UNITS – VERSION i-AD (air-cooled) &
i-AT (water-cooled )
The i-AD and i-AT series units feature two different cooling sys-
tems, which cannot be active at the same time.
One primary chilled water system (CW) provided by a chiller
installed on site, and a secondary direct expansion system (DX),
which also acts as backup.
The activation set points of these two circuits can be seen in the
User terminal manual.
The i-AD units are fitted as standard with EC radial fans in the
standard version.
Version i-AD (air-cooled)
The i-AX series units use air as the cooling fluid, and are there-
fore combined with an outdoor air-cooled condenser (supplied
separately).
The STD version includes the condenser control function with
EC fan speed control in combination with i-BRE remote con-
densers.
The MODULATING version features condenser fan speed con-
trol, so as to maintain correct refrigerant condensing pressure.
The i-AD units are supplied with valves for closing and isolating
the refrigerant circuit and to assist service operations.
A second non-return valve, to be fitted by the installer at the con-
denser outlet on the liquid line, is recommended during operation
in winter, to prevent migration of the refrigerant charge from the
liquid receiver to the outdoor condenser, with consequent low
pressure alarms.
Outdoor air-cooled condenser
The indoor unit can be connected to different types of BRE (axi-
al-flow fans with asynchronous motor) and i-BRE outdoor con-
densers (axial-flow fans with EC motor), standard or low noise
version, and with special coil treatment.
For more specific information see the manual on the outdoor air-
cooled condensers.
Note 1
: unit and outdoor condensers supplied separately
Note 2
: the indoor unit is delivered charged with nitrogen at
near-atmospheric pressure.
The outdoor condenser, on the other hand, is supplied pres-
surised with dry air (around 3 bars)
Note 3
: the customer is responsible for properly making the
connections between the indoor and outdoor units, as clearly
described in this manual, and for ensuring the required gas and oil
charge, where necessary.
Water circuit
The unit is fitted with a modulating 3-way valve to control the
flow of cooling fluid to the indoor heat exchanger and maintain
the desired conditions.
Summary of Contents for i-accurate
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