Emergency Cooling Version (Efc 48 Vdc / 230 Vac); Electrical Protection; Starting And Stopping; First Start - Emerson Liebert HIROSS TD 06 Service Manual

3.5 --- Emergency cooling version
(EFC 48 VDC / 230 VAC)
When this option is available install the supply cable as de-
scribed in par. 3.2 and connect them to switch QF2 according to
the diagram.
In the 48---VDC units respect the polarity "+" and " ---".

3.6 --- Electrical protection

Caution. For the electrical protection of the conditioner an ade-
quate switch with current protection must be installed in the
power supply line. For the selection of of the disconnect switch
please refer to the Tab. 4.

4 --- Starting and stopping

4.1 --- First start ---up (or after a long halt)
Before starting the air conditioner do check if the power supply
voltage and frequency comply with those on the identification
plate of the unit. After this, it is possible to power the unit operat-
ing on the main switches QF1 and QF2 (if present) that can be
reached removing the front middle panel. For the units
equipped with Microface microprocessor control, depending
on the installed interface and after having operated on the
switches to ensure a suitable power supply, it is possible to start
and stop the unit following the instructions here below.
In the units equipped with MICROFACE interface:
the unit is started pressing the switch with LED;
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the unit is stopped pressing the switch with LED.
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In the units supplied with HIROMATIC interface:
start by pressing the ON ---OFF push button on the Hiroma-
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tic (confirmed by SYS.ON on the display);
stop by pressing the push button ON ---OFF on the Hiroma-
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tic (confirmed by SYS.OFF. on the display).
Important! In both cases it is extremely important to consider
the status of the digital input of the Microface microprocessor
control managing the unit ON ---OFF (see relevant handbook
and wiring diagram).
Indeed, for the unit to start (operating on the switch with LED of
the Microface interface, or on the ON ---OFF key of the HIROMA-
TIC INTERFACE), the digital input must be bridged (see wiring
diagram).
Check that there are no active alarms; wait until the system
reaches the standard operation and then make the following
checks:
check that the fans are working correctly;
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make sure that the temperature is controled and the com-
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pressor and the heaters (optional) work when required;
make sure that the speed adjuster of the fan of the condens-
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ing section controls the fan operation (see chap. 7).
Note: Turn the main switches QF1 and QF2 (if present) off only
if the unit is stopped for a long time.
4.2 --- Start ---up with low outside tempera-
ture
In case of low outside temperature (<0_C), the unit start---up is
helped by the delay time of the compressor low pressure alarm,
within which the pressures in the refrigerating circuit reaches
the standard operation values.
4.3 --- Self---test
At each start it is possible to activate from the Microface micro-
processor control the Self ---test function, checking automatical-
ly and sequentially the components such as compressor, fan,
heaters, Freecooling damper, alarms and warnings. All this
leads to a remarkable decrease of the time needed for starting
the unit, to the elimination of manual control and the ablity to
perform a fast check of the main components for the correct
conditioner operation.
5 --- Operation
The unit operation is completely automatic. The below se-
quence explains (with the assistance of Fig. 5 ---Operation dia-
gram) how the unit operates (see also Fig. 7 --- Refrigerating
circuit):
1) The temperature sensor (1), positioned inside the condi-
tioned room, informs the control about the condition of the
return air.
2) The control compares the information received with the set
values of Set Point (= min. inner temperature) and Propor-
tional Band (and differential in the versions with Freecooling
option), setting the conditioner for the air treatment in the fol-
lowing modes:
Cooling (Fig. 5)
After switching the unit on, the evaporating fan (8) is immediate-
ly started while the compressor (10) is started when the temper-
ature of the room to be conditioned exceeds the set value. The
condensing fan (9) is automatically started when the condens-
ing pressure changes. The air taken in by the centrifugal fan (8)
enters the unit through the suction inlet (1), immediately passes
through the filter (2) and then the evaporator (5). The cold refrig-
erant flows inside the evaporator coil (5), thus cooling the air
crossing it. The treated air is conveyed in the conditioned room
through the supply outlet (3). The heat taken from the room and
the one generated by the conditioner motor operation are dis-
posed through the condenser (7) placed in the lower part of the
unit and cooled with outside air via the condenser fan (9). The
fan operation is managed with Variex, see par. 5.1 as a function
of the condensing pressure. For the operation logics of the con-
trol see chapter 6.
Heating (optional)
The air heating is achieved by means of electric heaters (6), lo-
cated in the air flow and activated according to the logics set on
the control (see chapter 6).
The manual reset of the safety thermostat, placed on the electri-
cal heaters, is carried out through the front.
Freecooling -- (Fig. 5)
When the outdoor temperature is lower than the indoor, the inte-
grated modulating damper will open/close to cool the room with
external air: compressor is off. The exhaust warmer air is auto-
matically rejected outside through the unit, without any addi-
tional louver (e.g. overpressure damper). The parameters can
be adjusted. A dedicated temperature sensor is present in the
air delivery section to prevent the air from entering the room at
too low temperatures (adjustable parameter). The unit is further
equipped with a washable metal filter next to the outside air suc-
tion inlet. When the expected conditions occur, the servocontrol
(4), managed by the Microface control, opens the movable
damper separating the flows of the inside and outside air. In this
way the outside air, drawn in by the fan (8), flows inside the room
and is discharged through the openings of the freecooling
compartment. The modulation of the damper is determined as a
function of the set point value to bemaintained and of the intake
air temperature (see Chap. 6).
5.1 --- Adjustment of the condenser fan
speed
A sensor is positioned so as to detect the condensing pressure
of the refrigeration gas. On the basis of this information, an elec-
tronic device (Variex) modulates the fan speed in order to keep
the condensing pressure within the allowed values. In this way,
besides optimizing the compressor operation, you can have a
reduction of the sound pressure level (mainly during the night),
an easier start---up of the compressor at low temperatures and
some energy saving.
For the calibration of the speed adjuster refer to chap. 7.
pag. 2 English