085 408 076a
13
8.4
Power connection
CAUTION:
• The cooling unit must be connected to the mains by means of a
disconnecting device with a contact gap of at least 3 mm when
switched off.
• No temperature control must be series-connected to the cooling
unit feed.
The fuse as indicated on the ID plate must be series-connected
as line protection.
• Power connection and repairs, if applicable, may only be car-
ried out by authorized trained electricians.
Power supply connection (mains):
Both mains voltage and frequency must correspond to the nominal
values indicated on the ID plate of the cooling unit.
• The installation of the power cable is not subject to any special
requirements
Attention: The cooling unit may be damaged if the
voltage is too high.
Refers to cooling units for nominal voltages 400 V/440V.
As an option, some units, different to the standard (400 V/
440 V), may be connected to a different mains voltage (For
voltage range see Techn. data sheet). The feed cables on
the transformer primary must be unclamped for this.
Door contact:
The door contact is supplied form the cooling unit with an extra-low
voltage (<20V, 20 mA).
• In order to avoid any disruptive influences, it is recommended
that a sheathed cable with twisted pair leads be used. The screen
can be secured on one side to the PE connection point provi-
ded on the cooling unit.
• If the use of sheathed cables is not possible, during installation of
the cables it must be ensured that they are not routed in the imme-
diate vicinity of potential interference sources (e.g. supply lines, com-
ponents with relatively high electromagnetic emission).
WARNING: No external voltage may be applied.
If no door-contact switch is used, the connecting contacts
are to be bridged.
Centralised fault indication:
For connection of the fault signal line there are 2 connection contacts
and/or connecting lines available (see circuit diagram on the Techn.
data sheet)
The installation of the fault signal line is not subject to any special
requirements.
WARNING: The contact may be loaded with
max. 230 V, 1A.
9
Operating Conditions
• Voltage must be within ± 10 % of the value indicated.
Frequency must be within ± 3 Hz of the value indicated.
• Ambient temperature must be below 45 °C (for options see Techn.
data sheet).
• Use the unit such that the cooling capacity suits the actual de-
mand.
• Use refrigerant as indicated only.
• Use genuine spare parts only.
10 Putting into operation and function
10.1 General remarks
The cooling unit is provided with an electronic control system. The
drawn-in switch cabinet internal air temperature is measured by a
temperature sensor. By means of a DIP switch on the control board,
different switch cabinet temperatures as well as upper limit temperatures
can be selected (see Techn. data sheet).
Exceeding the limit temperature generates an alarm.
Warning!
Ambient conditions and temperature in the switch cabinet must
be in accordance with the values indicated in the Techn. data
sheet.
Warning! Too little heat transfer at the heat exchan-
ger in the external circuit (condenser).
The cooling unit may only be operated with cover, otherwi-
se heat dissipation at the condenser is not sufficient, and
the cooling unit may be damaged.
Immediately after the switch-on of the service voltage, the
unit goes into the start-up/test mode. After that the evapo-
rator fan continues to run. Compressor and condenser fans
run on as required (the temperature of the switching thres-
hold (T
set
) has been reached, or are switched off (tempera-
ture lower than switching threshold (T
set
)).
• Free discharge of any condensate produced must be provided
to ensure trouble-free operation.
10.2 Indicator elements
The cooling unit has an operational display in the form of a LED on the
external hood of the unit. If the light of this indicator remains on when
the supply voltage is applied it shows that the unit is in the normal
operating mode. If a fault occurs or if the unit is in the start-up or test
mode, this indicator lights up in various flashing sequences which make
it easier to diagnose fault in the unit (see Sections 10.4 and 13)
10.3 Test mode / start-up
The test mode is basically activated after renewed connection of
the supply voltage and is independent of the instantaneous ambient
conditions when the door contact is closed.
First of all the unit runs through a start-up mode lasting 30 seconds
which is followed by a test mode lasting 30 seconds.
