Cooling And Heating Unit; Unit With Freecooling - Liebert HIROSS Hisp SE Serie Manual De Usuario/ Instalacion

If the system is connected to the Hiromatic interface, it
is possible to set a different rotation control.
If several units are simultaneously working with the
same set point, the temperature used for the control is
the average of the detected ones; further, in the opera-
tion with compressor, the proportional band is divided
in as many parts as twice the number of units belonging
to the system, so as to shut the total available refriger-
ating capacity.

5.2 --- Cooling and heating unit

5.2.1 --- Control logic
The control algorithm is based on a one--- step adjust-
ment for the compressor--- aided heating and cooling.
The control manages all its lags in the activation of the
compressor, as previously described, so as to guaran-
tee its correct operation and to make it function as long
as possible.
Dead band
!P @ P band
Heating Set Cooling
Fig. J --- Operation of the cooling + heating unit
5.2.2 --- Start--- Stop
See Par. 5.1.2.
5.2.3 --- Alarm control
See Par. 5.1.3.
A further general warning is available signalling the
following abnormal condition:
S heater thermostat (reset on the thermostat).
Notes:
S the warning doesn' t cause the unit to stop.
S In case the safety heater thermostat intervenes, the
reset must be carried out on the thermostat, follow-
ing the same instructions as before.
5.2.4 --- Optional alarm card
See Par. 5.1.4.
5.2.5 --- Unit in stand--- by
See Par. 5.1.5.

5.3 --- Unit with Freecooling

5.3.1 --- Control logic
This option is also managed by the Microface micro-
processor control, which can be combined with the Hi-
romatic control to monitor all the operation parame-
ters of the unit (see the enclosed manual). The control
algorithm is based on a one--- step adjustment for the
compressor--- aided heating and cooling and on an ad-
justment of a Proportional --- Integrative type for cool-
ing in the Freecooling mode with setting of the set
point and proportional band (P) (Fig. K).
The control manages all its lags in the activation of the
compressor, as seen in the two preceding cases, so as to
guarantee its correct operation and to make it function
as long as possible.
The Freecooling mode is activated depending on the
difference (which can be set) between the internal and
!P @ P band
Cooling and
heating unit
° C
the external temperatures. This means that if the dif-
ference between the 2 temperatures increases beyond
a certain value, the unit automatically passes to the
Freecooling function: the compressor is de--- activated
and the analog output controls the 3--- point servomo-
tor of the damper. The damper opening is determined
as a function of the difference between the outside and
inside temperatures and as a function of the intake air
temperature, which cannot be lower than a preset safe-
ty value.
If the inside temperature exceeds the proportional
band by more than 20% for over 10 minutes, the unit
shifts to the compressor--- aided cooling and the Free-
cooling mode remains de--- activated for ½ hour. If the
inside temperature exceeds the proportional band by
more than 50% for over 2 minutes, the Freecooling
mode is de--- activated for ½ hour, and the unit shifts to
cooling by means of the refrigerating compressor.
Dead band
!P @ P band
Heating
Dead band
!P @ P band
Heating
Fig. K --- Operation of compressor, electric heaters and opening of
the Freecooling damper
5.3.2 --- 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.
5.3.3 --- 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
S heater thermostat (reset on the thermostat).
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. If the unit is
in stand--- alone, the high and low pressure alarms
9
!P @ P band
Freecooling
mode
Set Cooling
° C
!P @ P band
Compressor
cooling mode
Set Cooling
° C
English