Operating instructions
UP/BP/ULP/SLP 400 – 800 33
12 Safety devices
12.1 Adjustable overheat controller (TWW), Class 3.1 in accordance with DIN 12880
or adjustable temperature limiter (TWB), Class 2 in accordance with DIN 12880
Adjustable overheat controller (TWW), Class 3.1 and adjustable temperature limiter
(TWB), Class 2, work independently of the temperature control system in accordance
with DIN 12880.
The safety devices should be checked at regular intervals, e.g. once a month, once the
oven has stabilised at the desired temperature. To perform this safety check, reduce the
setting of the safety device until the red control light in the main switch module comes on.
After that, the safety device can be set again.
working
temperature
ϑ
t
safety temperature
Note:
During programmed operation the safety
device has to be set sufficiently higher than
the maximum working temperature or at the
upper temperature limit of the oven.
°C
alarm set
Protection of the load against overtemperature:
Using the control knob, set the adjustable overheat
controller to a reasonable amount (e.g. 5°C)
The display always shows the set temperature of the
TWW or TWB.
After the temperature has stabilised, the setting of the TWW
or TWB should be moved down using the control knob until
it just does not operate. This provides improved protection of
a sensitive load against overtemperature in case of failure of
the working temperature controller. (approx. 3ºC; approx. 0,5
ºC on incubators)
This lowering of the setpoint to just above the actual
stabilised temperature should take place very slowly, one
degree at a time.
Warning! Excessively close adjustment of the
TWW/TWB can cause unintentional operation release i
f
the oven is disturbed (e.g. opening of the door).
Note:
Changing the displayed setpoint is only possible if the alarm set button is held down
at the same time. This avoids unintentional changes.
Turning the rotary knob rapidly changes the setpoint in large steps; turning it slowly
changes the setpoint in single steps.