6Rittal cooling unit assembly and operating instructions
3 Device descriptiKJ
energy from the enclosure air in the evaporator coil.
The whole cycle begins again.
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Rittal enclosure cooling units are fitted with a control-
ler for setting the functions of the cooling unit.
Depending on the design, this is either a Basic
controller (operating status display via LED) or an
e-Comfort controller (display plus extended func-
tions, see chapter “6 Operation”, page 21).
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The serial unit interface X2 allows you to create a bus
connection with up to ten cooling units using the
master-slave cable (shielded, four-wire cable, Model
No. 3124.100). This allows you to implement the fol-
lowing functions:
– Parallel unit control (the cooling units in the network
can be switched on and off simultaneously)
– Parallel door status message (“door open”)
– Parallel collective fault message
Data is exchanged via the master-slave connection.
During commissioning, assign an address to each
unit that also includes the identifier “master” or
“slave”.
324 Safety devices
– In the cooling cycle, the cooling units (with the ex-
ception of type 3302.xxx) have a tested pressure
switch to EN 12 263 which is set to maximum PS
(permissible pressure); this operates via an auto-
matic reset device whenever the pressure drops
again
– Temperature monitoring prevents the evaporator
coil from icing over. If there is a risk of icing, the
compressor switches itself off and automatically
switches itself back on again at higher tempera-
tures
– The refrigerant compressor and the fans are
equipped with thermal winding shields to protect
against excess current and excess temperatures
– In order to allow a reduction of pressure inside the
compressor and hence a safe restart, once it has
been switched off (e.g. upon reaching the set tem-
perature via the door limit switch function or via de-
energising), the device will switch back on with a
delay of 180 seconds
– The device has floating contacts on the connection
pins (terminals 3 – 5), via which system messages
from the device may be polled, e.g. using a PLC
(1 x change-over contact Basic controller, 2 x nor-
mally open contacts e-Comfort controller)
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At high levels of humidity and low temperatures in-
side the enclosure, condensation may form on the
evaporator coil.
The cooling units (except 3302.xxx, 3303.xxx and
3361.xxx) have automatic, electric condensate
evaporation. The thermal component used for this
purpose is based on self-regulating PTC technology.
Condensate arising on the evaporator coil is collect-
ed in a tank in the external circuit of the cooling unit,
and partially evaporated via the airflow. When the
water level rises, the water enters the PTC thermal
component and is evaporated (through-flow heater
principle). The water vapour streams out of the cool-
ing unit with the airflow from the external fan.
The PTC thermal component is permanently con-
nected and has no switchpoint. It is protected
against short-circuits with miniature fuses (F1.1,
F1.2). If the fuse has tripped, any condensation is
drained off via the safety overflow.
For unit types 3302.xxx, 3303.xxx and 3361.xxx, the
condensate is routed downwards out of the unit via a
drain pipe on the evaporator coil divider panel. For
this purpose, a hose must be connected to the con-
densate nozzle (see “4.4 Connecting the conden-
sate discharge”, page 12). External condensate
evaporators are available as accessories for these
unit types (refer also to the accessories in the Rittal
Catalogue).
326FiHter Iats
The entire cooling unit condenser is covered with a
dirt-repelling, easy-to-clean RiNano coating. In many
applications, therefore, the use of filter media is
unnecessary, particularly with dry dusts.
For dry, coarse dust and lint in the ambient air, we
recommend installing an additional PU foam filter
mat (available as an accessory) in the cooling unit.
Depending on the incidence of dust, you will need to
replace the filter mat from time to time.
For air containing oil condensate, we recommend
the use of metal filters (also available as an accesso-
ry). These may be cleaned with suitable detergents
and reused.
Function of the filter mat monitor (with e-Comfort con-
troller only):
Dirt on the filter mat is automatically determined by
measuring the temperature difference in the external
circuit of the cooling unit. As the level of filter mat soil-
ing increases, the temperature difference will in-
crease. The setpoint value of the temperature differ-
ence in the external circuit adapts automatically to
the relevant operating points in the performance
diagrams. Hence there is no need to readjust the
setpoint value for different unit operating points.
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The cooling unit may be operated with a floating door
limit switch connected. The door limit switch is not in-
cluded with the supply (available as an accessory,
Model No. 4127.010).
The door limit switch function causes the fans and
the compressor in the cooling unit to be switched off
after approximately 15 seconds when the enclosure
door is opened (contacts 1 and 2 closed). This pre-
vents the formation of condensation inside the enclo-
sure while the enclosure door is open. In order to
