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English
Liebert HPM --- A/W/F/D/H
denser is fitted with an head--- pressure regulating valve (8)
for the automatic control of condensing pressure.
The units operate with mains water or closed circuit with
an external Dry Cooler. When operating in a closed circuit,
to avoid undesired ice formation in wintertime, it is advisable
to use water/glycol mixture: refer to Chap. 5 for the percent-
ages to be used at minimum ambient temperatures. Dry
Coolers are available as an option; water ---glycol mixture
and circulation pump(s) are normally supplied by others.
If mains water is used, a mechanical filter must be fitted in the
water circuit to protect the plate condenser (2) (for other in-
formation see the Service Manual).
To reduce water and energy consumption (pump), it’s advis-
able to adopt a cooling water control valve (by the user), able
to stop water feeding when unit is off.
Unit microprocessor control gives a 24V contact (10VA max,
please refer to the relevant Wiring Diagram, 58 and G termin-
als) to drive that valve.
Note. The water ---cooled Liebert HPM versions are filled
with the complete charge of the requested refrigerant
(standard R410A).
SxxOW
MxxOW
Units
1
2
3
9
4
8
5
6
7
Cooling Water
2.1.4 --- Freecooler units --- Version F
Freecooling
mode
The Freecooler unit cools the air flow by means of the air re-
frigerant c o il ( 5) i n di re c t expansi on rows [dir ect expansion
mode] or, as an alternat ive, the air/water coil (5) in freecool-
ing rows [freecooling mode]. Wheneverthe outdoortemper-
ature is at least 5 degrees below the indoor return temperat-
ure, the water flow is cooled by an external Dry Cooler ( 10)
and passes through the coil (5). When the externaltemperat-
ure is higher than ZET (Zero Energy Temperature), the water
exchanges heat with the refrigerant in the water---cooled
plate condenser (2). When the external temperature is below
ZET, the water is cooled as much as to cool the room air dir-
ectly in the air/water coil (5, freecooling rows).
Water/glycol circuit
The units operate with water in closed circuit with an ex-
ternal Dry Cooler (10), cooled by the outside ambient air.To
avoid undesired ice formation in wintertime, it is advisable to
use water/glycol mixture: refer to the Service Manual for the
percentages to be us ed at minimum ambient temperatures.
The circulation of the water---glycol mixture is forced (the
pump (11) and the wat er---gl yco l mixtur e are not supplied).
The unit is provided with 2---way modulating valve (12) to
control the glycoled---water flow passing through the water/
glycol coil. A solenoid valve (13) allows the water flow to the
condenser.
The opening or closing signals , generated by the el e ctronic
cont rolle r, manage the valve actuator movement in order to
maintain the desiderd conditions in the conditioned room.
SxxOF
MxxOF
Units
1
9
4
8
5
6
7
10
11
3
13
2
12
2.1.5 --- Air---cooled condenser dualfluid units
Version D
Dualfluid
modes
The Dualfluid unit cools the air flow by means of the air refri-
gerant coil (5) in direct expansion rows [direct expansion
mode: see refrigeration cir c uit] o r, as an alternative, the air/
water coil (5) in the chilled water rows [chilled water mode].
SxxUD
MxxUD
L8F U D
Units
Chille d Wate r (fro m Cu s t o mer)
8
9
1
5
6
2
7
3
4
2.1.6 --- Water---cooled condenser dualfluid units
V
ersion H
Dualfluid mode
The Dualfluid unit cools the air flow by means of theair---refri-
gerant coil (5) in direct expansion rows [direct expansion
mode: see refrigeration cir c uit] o r, as an alternative, the air/
water coil (5) in the chilled water rows [chilled water mode].
SxxOH
MxxOH
Units
Co o ling Wat er
Chilled Wat er
(from Customer)
1
2
3
9
4
8
5
6
7
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