Table of Contents
Advertisement
FREE COOLING UNITS – VERSION AF
The 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 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 AF units are supplied 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 cooling fluid must be circulated using pumps (not supplied as
standard).
Dry coolers in the correct size are available as options.
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 free cool-
ing.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.
AF - water cooled
6
EN
DUAL FLUID UNITS – VERSION AD (air-cooled) & AT
(water-cooled)
The AD and AT series units feature two different cooling systems,
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 unit AT and AD are supplied as standard with EC radial fans in
the standard version.
Version AD (air-cooled)
The AD series units use air as the cooling fluid, and are therefore
combined with an outdoor air-cooled condenser (supplied sepa-
rately).
The MODULATING version features condenser fan speed control,
so as to maintain correct refrigerant condensing pressure.
The 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 outdoor
condensers, standard or low noise versions, with special treatments
on the coils.
For the corresponding information refer to the manual on 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 pressurised with dry air (around 3 bars)
Note 3: the customer is responsible for properly making the con-
nections between the indoor and outdoor unit, 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.
AD - air cooled
ACCURATE AX - AW - AD - AT - AF
Hide quick links:
Advertisement
Table of Contents
