Hiflex
4 All Versions
English
2.3 - Version D
Air-condensed dualfluid units
Refrigerating circuit
The 8 models are provided with a single re
frigerating circuit, the units 9 have two re
frigerating circuits. The refrigerating circuit
includes the compressor and the thermal
expansion valve with an external equalizer
controlling the refrigerant flow to the evapo
rator so as to keep a steady overheating de
gree. Before the thermal expansion valve
there is a sight glass enabling the visual
check of the refrigerant charge. A dryer fil
ter is installed in the liquid line for better
cleaning and less humidity in the circuit.
The welded steel liquid receiver is avail
able in the refrigerating circuit to enable the
constant and even refrigerant flow to the ex
pansion valve. On-off valves are installed
as standard to help the extraordinary main
tenance of the circuits. For a safe opera
tion, during the start-up it is advisable to
install the non-return valve (supplied as
optional on request) on the connection of
the refrigerant with the external condenser
to protect the compressor from unexpected
refrigerant migrations (see installation dia
gramme).
A suitably sized safety valve is installed on the liquid receiver; the valve is equipped with flanged connec
tions to allow the refrigerant to be discharged outside through suitable pipes. All low temperature parts
of the refrigerating circuit are insulated. The refrigerating circuit is also provided with a high pressure
switch and a low pressure switch. The low pressure switch has automatic resetting, whereas - for safety
reasons due to possible high pressure in the compressor - the high pressure switch has manual reset
ting. The pressure switch calibration values are shown in the installation manual supplied with the ma
chine.
External condensing unit
The units are coupled with the air condensers of Liebert HIROSS wide range in the versions with stan
dard axial fans and with low noise axial fans.For technical data and performances refer to the relevant tech
nical documentation.The following paragraphs describe the suggested couplings for the HIFLEX units as
a function of the outdoor air temperature. The data given follow are approximate and must always be veri
fied on the basis of the specific performances and working conditions required.
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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