KBW (E6) 11/2016 page 76/147
12.3 Temperature safety device class 3.3 (option)
With the option over/under temperature protective device (temperature safety device class 3.3 acc. to DIN
12880:2007) the chamber is equipped with two additional safety devices (class 3.1 and class 3.2). The
combination of the safety devices is regarded as a safety device class 3.3.
The temperature safety device, class 3.3, serves to protect the chamber, its environment and the contents
from exceeding the maximum permissible temperature. Please observe the DGUV guidelines 213-850 on
safe working in laboratories (formerly BGI/GUV-I 850-0, BGR/GUV-R 120 or ZH 1/119, issued by the em-
ployers’ liability insurance association) (for Germany).
With safety device class 3.1 a maximum value for the temperature is set that the chamber will not ex-
ceed due to the regulatory function of the safety device class 3.1. This protection against excessively high
temperatures can, for example, serve to protect the chamber, its environment and the material under
treatment from excess temperatures.
With safety device class 3.2 a minimum value for the temperature is set that the chamber will not fall
below due to the regulatory function of the safety device class 3.2. This protection against excessively low
temperatures can, for example, serve to protect sensitive loads from under cooling.
Both safety devices are functionally and electrically independent of the temperature control system. If an
error occurs, they perform regulatory function.
Safety devices class 3.1 (8) and class 3.2 (9) are located in the left lateral control panel.
With option temperature safety device class 3.3, the safety controller (chap. 12.2) must be set
to the maximum limit value (70 °C / 158 °F).
Excess
temperature
Set-point
Insufficient
temperature
Figure 11: Temperature safety device class 3.3
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