Security Temperature Switch (STB) Release
STB = Security Temperature Switch
Security Temperature Switch (STB) protects heating elements from overheating! STB is released when the maximum
temperature of +90°C is exceeded. This can happen if the water level is low in the PE-box of the heating unit or if the
water circulation is not functioning correctly. Air bubbles cause the break of heat transmission! Possible reasons for this
may be: e.g. blockage or contamination (minerals/rust/lime/incrustation deposits) due to a damaged non-return flap/
shut-off valve, interrupted water flow, opened by-pass line, or if heating element is calcified.
In case of air bubbles in the water circuit
1. Bleed the pump (pos. 2)
2. Bleed the water circuit (pos. 12)
3. Check, whether the automatic vent valve has been correctly installed
(in a dry frost- and draught-protected room, at a highest point in the circuit)
Re-activation of the security temperature control switch (STB)
• Put main switch on 0 = OFF and separate the heating unit from the main current (two connections)
• Unplug the heating element
• Unscrew and take out the slotted screw out of the frontal side of heating element
• Heating element and STB have to be cooled down (otherwise STB does not snap in)
• Press the red STB pushbutton with an insulated screw driver
click sound can be heard
• Screw in the slotted screw
• Plug the heating elements
• Proceed to first startup (see page 21).
Heating element:
Temperature at the thermostat must be adjusted at min. +7°C to +10°C. Factory adjustment: +10°C.
Attention!
The higher the temperature is adjusted, the more lime deposits!
This increases the time and effort of maintenance and reduces the lifetime of the heating element.
For maintenance work screw out the heating element only at the hexagon steel plate.
30.10.2017 · Technische Änderungen vorbehalten · Technical data can be changed without prior notice · Des changements techniques reservés · Мы оставляем за собой право на технические изменения и
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дополнения, а также возможные опечатки. · 104.8116
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as in the case of first startup (see page 21)
STB
1
2
Montageanleitung
Mounting instructions
Instructions de montage
Инструкция по монтажу
Switch off from
the main current
before opening.