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BD / BF / ED / FD / FED (E3.1) 03/2019 page 33/106
7.2 Safety controller
The chambers are regularly equipped with an adjustable electronic safety controller. It serves to protect
the chamber, its environment and the contents against 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 employers’ liability insurance association) (for Germany).
Depending on the chamber type the safety controller acts as an over temperature safety device class 2
(“temperature limiter”) or class 3.1 (“temperature protection”) acc. to DIN 12880:2007.
Check the setting regularly and adjust it following any changes of the set-point.
• Safety controller class 2 (“temperature limiter”) with ED, FD and FED
The safety controller class 2 limits the temperature inside the chamber to the entered safety controller
set-point. In the event of a fault (if this maximum temperature is exceeded) the safety controller com-
pletely turns off the heating until manual reset. This status is reported visually by an alarm message
and, in case of the option audible alarm with activated buzzer (chap. 7.6) additionally by the buzzer
sounding.
If the safety controller class 2 has turned off the heating, we recommend proceeding as follows:
• Disconnect the chamber from the power supply.
• Have an expert examine and rectify the cause of the fault.
• Restart the chamber
• Reset the alarm message
• Safety controller class 3.1 (“temperature protection”) with BD and BF
The safety controller class 3.1 limits the temperature inside the chamber to the entered safety control-
ler set-point. In the event of a fault (if this maximum temperature is exceeded), it takes over the control
to this value. This status is reported visually by an alarm message and, in case of the option audible
alarm with activated buzzer (chap. 7.6) additionally by the buzzer sounding.
The safety controller keeps control of the chamber until the chamber temperature cools down below
the safety controller set-point value.
If the safety controller class 3.1 has taken over control, we recommend proceeding as follows:
• Disconnect the chamber from the power supply.
• Have an expert examine and rectify the cause of the fault.
• Restart the chamber
• Reset the alarm message
Function check:
Check the safety controller at appropriate intervals for its functionality. It is recommended that the author-
ized operating personnel should perform such a check, e.g., before starting a longer work procedure.
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