Liebert Hiflex Operator's manual

Hiflex
Product Documentation
English
cod.272055 - rev. 24.07.2002

Hiflex
English
INDEX
1 -The serie 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . .
1.1 - Unit coding 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . .
1.2 -Main features and advantages 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2 -Configuration 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..
2.1 - Version A 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . .
2.2 - Version W3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . .
2.3 - Version D4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . .
2.4 - Version H 5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . .
2.5 - Version F 6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . .
2.6 - Version C7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . .
2.7 -Hiflex Constant versione A 7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.8 -Hiflex Constant versione W 7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.9 - Air control 9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . .
2.10 -Dimensions and accessibility 9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3 -Operating limits 10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4 -Component features 11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.1 - Fan 11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . .
4.2 - Compressor 11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . .
4.3 - Coils 11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . .
4.4 -Frame and panels 11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . .
4.5 - Filters 12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . .
4.6 - Refrigerants 12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . .
4.7 - Electric board 12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . .
4.8 - Accessibility 12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . .
4.9 - Control system 12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . .
4.10 -Packing 13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . .
4.11 -Product quality and safety 13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5 -Condensing section 14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.1 - Air condensers 14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . .
5.2 - Water condensers. 17. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . .
5.3 - Dry coolers 17. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . .
6 -Technical remarks 20. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.1 - Fluid R407C. 20. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . .
7 -Electrical characteristics 22. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8 -Aeraulic features 27. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8.1 -Useful available heads 27. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..
9 -Sound Pressure Level 30. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.1 -Sound emission spectra 30. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10-Technical data and performances 35. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11-Optional 91. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . .
11.1 -Filters 91. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . .
11.2 -HP-FAN 93. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . .
11.3 -Reheating and humidity control (optional) 96. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11.4 -Humidification and dehumidification system 103. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11.5 -Water control valve (models W/H) 104. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11.6 -Flooding alarm (Liquistat) 104. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11.7 -Smoke alarm (Smokestat) 104. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11.8 -Fire alarm (Firestat) 104. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . .

Hiflex
English
11.9 - Fresh air 105. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11.10 -Suction and delivery ducts 105. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11.11 -Deadening cartridges for delivery channels - Silent Carts (models Over) 106. . . . . . . . . . . . . . . . . . .
11.12 -Delivery plenum with horizontal throw (models Over) 107. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11.13 -Grid with one deflection rank (models Over) 107. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11.14 -Base-frames: models TBD 107. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11.15 -Base-modules (models Over) 107. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11.16 -Automatic condensate drain pump 107. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11.17 -Non-return valve (models A and D) 108. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11.18 -Additional temperature and humidity sensor (EEAP) 108. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11.19 -Microprocessor control with graphic display HIROMATIC G 108. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11.20 -Deadening insulation coating 109. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11.21 -Duct with deadening insulation coating 109. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11.22 -Power supply at 230/3/50 110. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11.23 -Special packing 110. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11.24 -Air intake from the bottom (models Over) 110. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11.25 -Accessory combination 110. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
12 -Overall dimensions 111. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
The HIFLEX Product Documentation can also be surfed on the Web at the address: www.HIROSS.IT/pde/TDS/Hiflex
This document is password-protected. Ask for the password to your Dealer/Area Manager.

Hiflex
1All Versions English
1 - The serie
HIFLEX is the new series of air conditioners developed by Liebert HIROSS to allow maximum flexibility
of application in technological environments, from data processing centers to manned control rooms and
electronic centers for telecommunication. This series includes units with a rated cooling capacity ranging
from 5 to 40 kW.
1.1 - Unit coding
A mark with four alphanumeric characters identifies the model.
4LOA
is the numeric value
identifying the size of
the unit (4-6-8-)
Models 5-7-9 are
double.
MSmall type - R22
SSmall size - R22
LLarge size - R22
PSmall size - R407C
GLarge size - R407C
ADirect expansion unit with external air
cooled condenser
CChilled water unit
DDirect expansion unit and chilled water
unit (DUALFLUID) with external air
cooled condenser
FDirect expansion unit and chilled water
unit (FREECOOLER) with water cooled
condenser - one water circuit.
HDirect expansion unit and chilled water
unit (DUALFLUID) with water cooled
condenser
WDirect expansion unit with water cooled
condenser
Uunderfloor air flow (Under)
Oupward air flow (Over)
Cconstant
1.2 - Main features and advantages
The air conditioners of HIFLEX series have the following features:
High sensible cooling capacity; high EER (Energy Efficiency Ratio)
Total front accessibility for the maintenance
Low acoustic emission
Exact electronic control by microprocessor
Small plant dimensions

Hiflex
2All Versions
English
2 - Configuration
Here is a short description of the peculiar features of each of the six available versions.
2.1 - Version A
Direct expansion air-condensed units
Refrigerating circuit
The 4-6-8 models are provided with a
single refrigerating circuit, the units
5-7-9 have two refrigerating circuits. The
refrigerating circuit includes the compres
sor and the thermal expansion valve with an
external equalizer (or in the M version, the
cappilary) controlling the refrigerant flow to
the evaporator so as to keep a steady over
heating degree. Before the thermal expan
sion 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 cir
cuit. The welded steel liquid receiver is
available in the refrigerating circuit to en
able the constant and even refrigerant flow
to the expansion valve. On-off valves are
installed as standard to help the extraordi
nary maintenance of the circuits.
For a safe operation, 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 exter
nal condenser to protect the compressor
from unexpected refrigerant migrations
(see installation diagramme). A suitably sized safety valve is installed on the liquid receiver; 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 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 pres
sure switch has manual resetting. The pressure switch calibration values are shown in the installation
manual supplied with the machine.
The units are supplied without the external condenser and with nitrogen-pressed refrigerating circuit. The
customer himself has to make the connection with the external condenser and the refrigerant charging.
All the instructions for the necessary operations are contained in the installation manual.
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 below are approximate and must always be veri
fied on the basis of the specific performances and working conditions required.

Hiflex
3All Versions English
2.2 - Version W
Direct expansion water-condensed units
Refrigerating circuit
The 4-6-8 models are provided with a
single refrigerating circuit, the units
5-7-9 have two refrigerating circuits. The
refrigerating circuit includes the compres
sor and the thermal expansion valve with an
external equalizer controlling the refriger
ant flow to the evaporator so as to keep a
steady overheating degree. Before the
thermal expansion valve there is a sight
glass enabling the visual check of the re
frigerant 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 standard to help the extraordi
nary maintenance of the circuits.
A suitably sized safety valve is installed af
ter the condenser; the valve is equipped
with flanged connections to allow the refrig
erant 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 auto
matic resetting, whereas - for safety rea
sons due to possible high pressure in the
compressor - the high pressure switch
has manual resetting. The pressure switch
calibration values are shown in the installa
tion 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 chill
er. 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 gly
col percentage (refer to the installation manual for the suitable percentages). The circulation of the water-
glycol mixture is forced (the pump is not supplied). If throwaway water or tower water is used, when instal
ling the unit fit a mechanical filter on the water line to protect the condenser against possible impurities
contained in the water (for the condenser cleaning see the installation manual).

Hiflex
4All 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.

Hiflex
5All Versions 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.

Hiflex
6All Versions
English
2.5 - Version F
Freecooler 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.
On-off valves are installed as standard 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 insu
lated. The refrigerating circuit is also pro
vided with a high pressure switch and a low
pressure switch. Il pressostato di minima è
a riarmo automatico, mentre, per ragioni di sicurezza derivanti dalle possibili alte pressioni nel compres
sore, il pressostato di massima è dotato di riarmo manuale. I valori di taratura dei pressostati sono indicati
nel manuale di installazione, fornito a bordo macchina.
The low pressure switch has automatic resetting, whereas - for safety reasons due to possible high pres
sure in the compressor - the high pressure switch has manual resetting. The pressure switch calibration
values are shown in the installation manual supplied with the machine.
Condenser
The units are provided with built-in stainless steel water condensers 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 water in closed circuit with external chill
er. 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 gly
col percentage (refer to the installation manual for the suitable percentages). The circulation of the water-
glycol mixture is forced (the pump is not supplied). To minimize water consumption and the condensing
pressure check during the different seasons of the year, the unit is provided with a water register supplied
as standard on the machine.
Hydraulic circuit
The unit is provided with a 2-way modulating valve, complete with incremental motor for the water flow
control to the freecooling coil; the opening or closing signals, generated by the electronic control, manage
the valve in order to keep the ambient temperature at the required value.