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Start-up/shutdown
Measures to be carried out in the event of the...
High limit safety cut-out (STB)
The high limit safety cut-out is part of the boiler. It is
located behind the programming unit under the front
top panel.
Note
If the high limit safety cut-out responds, it must be
manually reset.
When the function responds:
The high limit safety cut-out responds if the boiler
water temperature exceeds 95 °C.
The fan in the boiler is stopped down and the air
dampers are closed. This reduces the boiler output
and lowers the flow temperature. Boiler overheating is
prevented.
Resetting the function:
Note
The high limit safety cut-out can only be reset
(unlocked) once the boiler water temperature has
reached approx. 70 °C.
!
Please note
If it is not reset (unlocked), it inhibits the safety
equipment function and can result in system
damage.
Always carry out the following steps.
A
1.
Fig. 11
Thermally activated safety valve
The thermally activated safety valve is installed by
your heating contractor. It is connected to the safety
heat exchanger integrated in the boiler. The safety
heat exchanger is at the back of the boiler.
20
(cont.)
1. Slide the cover on the programming unit to the
right.
2. Press green button
out. A quiet "click" will be audible. The high limit
safety cut-out has been reset.
3. Close the programming unit cover.
4. Acknowledge the excess temperature on the pro-
gramming unit of the control unit with
Note
If the high limit safety cut-out responds several times
within a short period, check the cause. Check whether
the system can absorb any more heat. Notify your
heating contractor.
Note
Observe the instructions in the manufacturer's docu-
mentation of the thermally activated safety valve.
The boiler must be equipped with a thermally activated
safety valve.
of the high limit safety cut-
A
d
.
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