Rittal SK 3178800 Assembly And Operating Instructions Manual Download

Page: 27 / 56

Rittal enclosure cooling unit

7 Operation

7.4

Setting options via the display

7.4.1

Selecting a control mode

The cooling unit controls cooling output according to
one of the following three temperature values:
–

Internal temperature (factory setting):

The tem-

perature at which air is drawn out of the enclosure into
the cooling unit.

–

External sensor:

The temperature measured with an

external temperature sensor at a so-called hot spot in
the enclosure.

–

Outlet temperature:

The temperature measured

with an external temperature sensor at the cold air out-
let from the cooling unit.

Control mode "external sensor"

Please observe the following when selecting the sensor
position: The sensor must

not

– be influenced directly by the cold air expelled from the

cooling unit,

– be influenced by external heat sources or heat radia-

tion,

– be exposed to humidity,
– have its connection cable laid in the vicinity of AC ca-

bles,

– be exposed to different temperature levels within the

first 10 cm of the connection cable.

The sensor

must

– be located within the effective range of the cooling

unit,

– be surrounded by adequate moving air which has

blended well with the air expelled by the cooling unit,

– be at an adequate distance from solid and liquid sub-

stances.

Control mode "outlet temperature"



Attach the temperature sensor to the marking in front
of the cooling unit's cold air outlet using a cable tie
(fig. 52).

Fig. 52:

Temperature sensor in front of cold air outlet (example
illustration)

Selecting a control mode



Briefly press the Home key in the "tSE" menu.
The sub-menu "Con" (control mode) will appear for
you to select the control mode.



Choose your preferred control mode using the arrow
keys.
– "Int": Control mode "Internal temperature"
– "ESt": Control mode "External sensor temperature"
– "Out": Control mode "Outlet temperature"



Keep the Home key pressed down for around 3 sec-
onds to switch to the next menu up.
If the control mode is altered, the message "ACC" will
appear in the display for approximately 1 second. After
that, the next menu up "Con" will appear.

7.4.2

Setting the target temperature



Briefly press the Home key in the "tSE" menu.
The sub-menu "Con" (control mode) will appear for
you to select the control mode.



Use the arrow keys to select the "SP" (setpoint) menu
and briefly press the Home key again.
The currently set temperature will be displayed.



Change the value using the arrow keys until you reach
the required set temperature.
Depending on the control mode, the set temperature
can be changed within the following limits.

Note:
The external temperature sensor is available
as accessory from Rittal (see section 13 "Ac-
cessories").

Note:
The sensor element must not be in contact
with the enclosure.

Note:
To ensure the accuracy of the outlet temper-
ature, at least 50% of the total cooling output
should be installed as heat loss. The output
can be taken from the characteristic curve for
this unit.