Technical data

14
Fig. 9.3 Condensate discharge
9.4 Electronic evaporation
The SK 33xx.xx1 cooling units possess an
automatic electronic condensate evaporation
feature. Any condensate formed (see 9.3) is
collected in the external circuit of the cooling unit.
In the case of excessive condensate formation,
the evaporation function is activated via a
separate heating cartridge. The direct evapor-
ation principle provides for effective evaporation.
The relevant safety notes (see Point 4.) must be
observed!
10. Handling Instructions
Storage, maintenance, transport and disposal
As a maintenance-free, hermetically sealed
system, the cooling circuit has been filled in the
factory with the required amount of refrigerant,
and tested for leaks and subjected to a function
trial run.
The installed maintenance-free fans use ball
bearings, they are protected against moisture
and dust, and are fitted with a temperature
monitor. The life expectancy is at least 30,000
operating hours. The cooling unit is thus largely
maintenance free. All that may be required from
time to time is that the components of the external
air circuit are cleaned by compressed air.
The use of a filter mat is recommended only if
large particles of lint are present in the air, so
that blockage of the condenser is prevented.
(Filter mat replacement, fig. 7.1). Note: Prior to
any maintenance work, the power to the cooling
unit must be disconnected.
Storage temperature: The cooling units must not
be exposed to temperatures above +70°C.
Transport position: The cooling units must always
be transported upright.
Waste disposal: The closed cooling circuit
contains refrigerant and oil which must be
correctly disposed of for the protection of the
environment. Disposal can be carried out at
Rittal.
We reserve the right to make technical
modifications.
9. Technical information
The cooling unit (compressor refrigeration unit)
consists of four main components: the coolant
compressor, evaporator, condenser, and the
control or expansion valve, which are connected
by suitable pipework. This circuit is filled with a
readily boiling substance, the refrigerant. The
R134a (CH
2
FCF
3
) refrigerant is free from
chlorine. It has an ozone destroying potential
(ODP) of 0 and is therefore environmentally
friendly. A filter dryer which is integrated in the
hermetically sealed cooling circuit, provides
effective protection against moisture, acid, dirt
particles, and foreign bodies within the cooling
circuit.
9.1 Operation of the cooling unit
Fig. 9.1 Operation of the cooling unit
The compressor takes the gaseous refrigerant
from the evaporator and compresses it to a higher
pressure in the condenser. During this process
the temperature of the refrigerant rises above the
ambient temperature and heat can be dissipated
to the environment via the surface of the
condenser. Then the refrigerant is liquefied and,
by means of a thermostatically controlled
expansion valve, returned to the evaporator, where
it evaporates at low pressure. The heat required
for complete evaporation is drawn from the
enclosure interior causing it to cool down.
The cooling cycle is thus completed, the
aforementioned process of the heat transfer starts
afresh.
9.2 Safety equipment
The cooling circuit of the cooling unit has a
component-tested, high-pressure monitor to
EN 12 263, which is set to maximum PS (allowed
pressure) and operates via an automatic reset
device in case of recurring pressure drop.
Temperature monitoring will prevent the
evaporator from icing up. If there is a risk of icing
up, the compressor
is switched off and automatically switched on
again at higher temperatures. The refrigerant
compressor and the fans are equipped with
thermal winding protection switches against
excess current and excess temperatures.
9.3 Condensate discharge
A drain pipe fitted to the evaporator divider
panel ensures that any condensate which may
form on the evaporator (at high air humidity,
low temperatures inside the enclosure) is
drained away from the bottom of the unit.
For this purpose, a length of hose should be
fitted to the condensate pipe connection piece
(see fig. 9.3, if appropriate, remove the grille).
The condensate must be able to run off freely.
If the condensate is to be drained off over a
greater distance, then care must be taken that
the hose is free from kinks and a check for
correct drainage made.
Fan 2
Fan 1
Compressor
Evaporator
External circuit
Internal circuit
Expansion valve
Thermostat
Filter
dryer
Liquefier
PSA
monitor
H
English
11. Scope of supply and
guarantee
1 cooling unit, ready for connection
1 drilling template
1 sealing tape
1 set of mounting and operating instructions
1 plug-in terminal strip
Guarantee:
This unit is covered by a 1-year guarantee from the
date of supply, subject to correct usage (see also
Safety notices under heading 4.). Within this period,
the returned unit will be repaired in the factory or
replaced free of charge. The cooling unit is to be
used for the cooling of enclosures only. If it is
connected or handled improperly the
manufacturer’s guarantee does not apply and in
this case we are not liable for any damage caused.
03_S_3302_xxx_12_15_eng.fm Seite 12 Donnerstag, 8. Dezember 2005 12:15 12