Rittal SK 3302.series Assembly And Operating Instructions Manual - 6 Operation
6 Operation
Rittal cooling unit assembly instructions
23
GB
6.1.2 Operating and error display
The Basic controller monitors and controls the cool-
ing unit. It indicates the operating and error statuses
via the green and red LEDs (Fig. 34, nos. 3 and 4):
Tab. 3: Operating and error display of the Basic controller
You may also request the overtermperature mes-
sage (red LED illuminated) via an integral floating
contact on the connection clamp of the cooling unit
(system message relay with changeover contact,
see connection diagrams under “4.6.2 Installing the
power supply”, page
14
):
– Terminal 3: NC (normally closed)
– Terminal 4: C (connection of the supply voltage to
the system message relay)
– Terminal 5: NO (normally opened)
The definitions NC and NO refer to the de-energised
state. As soon as voltage is applied to the cooling
unit, the system message relay is picked up, so that
the relay contacts change status (contact 3 – 4 open;
contact 4 – 5 closed). This is the normal operating
state of the cooling unit. As soon as an error mes-
sage occurs or the power supply is interrupted, the
relay drops out.
6.1.3 Test mode for the Basic controller
The Basic controller is equipped with a test function
whereby the cooling unit commences cooling opera-
tion independently of the set temperature or door
limit switch function.
First you must dismantle the trim panel of the con-
troller.
• Switch off the mains voltage.
• Remove the louvred grille or infill panel in which the
controller is installed.
• Release the display lock from behind and pull it
forwards slightly.
Fig. 35: Releasing the trim panel of the Basic controller
LED
State
Cause
Solution
Green
(line)
Illuminated
Power supply on,
unit operational
–
Flashing
Only with installed door limit switch:
Enclosure door open
In order to avoid condensation, close the
enclosure door as quickly as possible.
Only with installed door limit switch:
Enclosure door closed
Check the position of the door limit switch
Red
(alarm)
Illuminated
The enclosure internal temperature is 5 K
above the set temperature
Check the temperature setting. Check the
condenser and clean if necessary. Check the
filter mat and replace if necessary. Check the
heat loss to be dissipated – it must not exceed
the useful cooling output of the cooling unit.
Flashing
High-pressure alarm in the cooling circuit
Check the temperature setting. Check the
condenser and clean if necessary. Check the
filter mat and replace if necessary. Check the
heat loss to be dissipated – it must not exceed
the useful cooling output of the cooling unit.
After rectifying the fault, you will need to reset
the Basic controller manually (see page 24
“6.1.5 Resetting the Basic controller”).
Only for SK 3302.xxx:
Connection to board interrupted
Check, replace board if necessary
Off
No
display
No power
Check power supply
Rotary current phase monitoring:
“LED off” = Incorrect phase connection
Swap phases