Adjustment Of The Condenser Fan Speed; Emergency Cooling (Optional); Microprocessor Controls; Cooling Only Unit - Liebert HIROSS Hisp SE Serie Mode D'emploi

function of the set point value to be kept and of the in-
take air temperature (see Chap. 5).
4.5 --- Adjustment of the condenser fan
speed
A sensor is positioned so as to detect constantly the
condensing pressure of the refrigerating gas. On the
basis of this information, an electronic device (Variex)
adjusts the fan rotation speed in order to keep the con-
densing pressure within the allowed values. In this way,
besides optimizing the compressor operation, you can
have a remarkable reduction of the sound pressure lev-
el (mainly during the night), an easier start--- up of the
compressor at low temperatures and some energy sav-
ing. For the calibration of the speed adjuster see chap-
ter 8.

4.6 --- Emergency cooling (optional)

This option is available for all those applications where
it is important to keep an airflow inside the room even
in the event of a mains power cut--- out. In this case the
units can be supplied by the emergency batteries at 48
V dc (or 24 V dc).
The intervention mode of the emergency system de-
pends on the state of the automatic switch QS1:
S QS1 = ON If the main power supply is not cut out,
the emergency system remains inactive; if there is
no voltage on the main power supply line, some en-
ergy is automatically collected from the emergency
batteries at 48 V dc (or 24 V dc) and it supplies the
fan of the evaporating section and the electronic
control through the 48 V / 230 V (or 24 V dc) trans-
former. So all functions of the unit are still man-
aged, allowing the inside air to recirculate (or the
outside air to flow in, if the unit is provided with the
Freecooling system) if the temperature inside the
room is not within the permitted range.

5 --- Microprocessor controls

The machine is available in four different operating
configurations:
1) only cooling unit;
2) cooling and heating unit;
3) unit with freecooling, only cooling;
4) unit with freecooling, cooling and heating.
In all versions the control display is remoted on the
metal box to be installed inside the room.

5.1 --- Cooling only unit

5.1.1 --- Control logic
This option is managed by the Microface microproces-
sor control, which can be combined with the Hiromatic
control to monitor all the operation parameters of the
unit (see the enclosed manual). The control algorithm
is based on a one--- step adjustment for the compres-
sor--- aided cooling: the control manages all its lags in
the activation, so as to guarantee its correct operation
and to make it function as long as possible.
English
P Band
Set
Fig. I --- Operation of the cooling only unit.
5.1.2 --- Start--- Stop
There are 2 ways for starting or stopping the unit:
a) the digital input of the Microface card;
b) the ON--- OFF push button on the Hiromatic inter-
face (optional).
Priority with Hiromatic: a) and b) must be regarded as
2 series contacts; the unit can operate only if all con-
tacts are on.
5.1.3 --- Alarm control
The 2 alarm contacts available on the terminal board
of the control panel can be used in this way:
1) General alarm:
S compressor low pressure
S compressor high pressure (reset on the pressure
switch)
S sensor fault
S memory fault
S fan fault
2) General warning --- signalling of various abnormal
conditions, among which:
S high temperature
S low temperature
Notes:
S both the alarm and the warning must be reset
manually on the Microface.
S An alarm causes the unit to stop and the unit in
stand--- by (if available) to intervene.
S The warning doesn' t cause the unit to stop.
5.1.4 --- Optional alarm card
Besides the components described for the standard
configuration, on the alarm card --- which can be sup-
plied as optional --- there are relay contacts to have the
following alarms separated:
1) Compressor high and low pressure
2) High temperature
3) Low temperature
4) Dirty filter alarm (if installed)
5) Fan fault
These alarms cause the unit to stop in the same ways as
described in the previous paragraph.
For a complete description of the alarms see the encl.
Microface manual.
5.1.5 --- Unit in stand--- by
The control of the unit in stand--- by is completely auto-
matic thanks to the possibility of connecting the Mi-
croface control. A unit in stand--- by starts in the event
of an alarm stopping the main unit; this occurs even if
the main unit is switched off or disappears from the
system, due to a fault on the control connecting bus.
The rotation of the units in stand--- by occurs automati-
cally every 24 hours, so as to allow a homogeneous
wear of the system components.
8
Cooling
unit
Cooling ° C
only