Technical data

BD / ED / FD 01/2006 page 29/49
8. Safety devices
8.1 Temperature safety device class 2 (DIN 12880) ED, FD
The temperature safety device class 2 protects the unit, its environment and the charging material
against impermissible excess temperatures.
Please also observe the regulations BGR 120 of the German professional association of the chemical
industry (formerly ZH 1/119 laboratory guidelines of the employers’ liability insurance association) (for
Germany).
In the event of a fault in the temperature controller, the safety device (7) permanently switches off the
unit. This status is reported visually by the indicator lamp (7a) and, in case of the option acoustic alarm
with activated buzzer (chap. 9.1), by the buzzer sounding.
The operation of the safety device (7) is checked by moving it slowly anti-clockwise until it is switched off.
The safety device cut-off is reported visually by the indicator lamp (7a) and, in case of the option acoustic
alarm with activated buzzer (chap. 9.1), by the buzzer sounding.
The safety device is then released again by pressing the reset button (7b) and the unit is switched on as
described.
Function:
The safety thermostat class 2 is functionally and electrically independent of the temperature control
device and switches off permanently at all poles.
Figure 6: Safety thermostat class 2
When the control knob (7) is set to the end stop, the safety thermostat class 2 acts as a unit protection
device. If it is set somewhat higher than the nominal temperature selected on the controller, it acts as a
material protection device.
When the safety device has switched off the unit, which can be seen from the illumination of the red
alarm lamp (7a) and, in case of the option acoustic alarm with activated buzzer (chap. 9.1), by the buzzer
sounding, perform the following steps:
• Disconnect the unit from the mains.
• Have the cause of the fault examined and rectified by a technician.
• Release safety thermostat class 2 by pressing reset button (7b).
• Restart the unit (see chapter 6).
Setting:
In order to check at which temperature the safety device activates, start the unit and set the required
nominal value on the temperature controller.
The scale division from 1 to 10 corresponds to the temperature range from 30°C up to 320°C and serves
as a setting aid.
(7)
(7a)
(7b)