Hiflex
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English
2.4 - Version H
Water-condensed dualfluid units
Refrigerating circuit
The 8 models are provided with a single refriger
ating circuit, the units 9 have two refrigerating cir
cuits. The refrigerating circuit includes the com
pressor and the thermal expansion valve with an
external equalizer controlling the refrigerant flow
to the evaporator so as to keep a steady overheat
ing degree. Before the thermal expansion valve
there is a sight glass enabling the visual check of
the refrigerant charge. A dryer filter is installed in
the liquid line for better cleaning and less humidity
in the circuit. On-off valves are installed as stan
dard to help the extraordinary maintenance of the
circuits. A suitably sized safety valve is installed
after the condenser; the valve is equipped with
flanged connections to allow the refrigerant to be
discharged outside through suitable pipes. All low
temperature parts of the refrigerating circuit are in
sulated. The refrigerating circuit is also provided
with a high pressure switch and a low pressure
switch. The low pressure switch has automatic re
setting, whereas - for safety reasons due to pos
sible high pressure in the compressor - the high
pressure switch has manual resetting. The pres
sure switch calibration values are shown in the
installation manual supplied with the machine.
Condenser
The units are provided with a built-in stainless steel water condenser with braze-welded plates; this ad
vanced exchanger type gives the highest efficiency in heat exchange. In addition, a certain oversizing of
the exchanger has been provided so as to reduce pressure drops (and energy consumption of the water
pump) as much as possible and thus to allow the unit to operate with the external chiller in closed circuit,
even at high outdoor temperatures.
The units shall operate with throwaway water, tower water or water in closed circuit with external chiller.
In the operation with closed circuit, the water is cooled by the outdoor air in a heat exchanger; in this case,
to avoid unwished ice formation during winter, it is advisable to obtain the mixture always with a glycol
percentage (refer to the installation manual for the suitable percentages). The circulation of the water-gly
col mixture is forced (the pump is not supplied). If throwaway water or tower water is used, when installing
the unit fit a mechanical filter on the water line to protect the condenser against possible impurities con
tained in the water (for the condenser cleaning see the installation manual).
Hydraulic circuit
The unit is provided with a 3-way modulating valve, complete with incremental motor for the water flow
control to the coil; the opening or closing signals, generated by the electronic control, adjust the valve in
order to keep the ambient temperature at the required value. Through a series of menus it is possible to
set all parameters on the control for a correct adjustment, i.e. set-points, proportional bands, proportional
or proportional+integral adjustment, integrating factor and valve feature. It is possible to adjust the valve
manually in closing position (coil side) by means of a suitable wrench.
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