Bosch Buderus SB625WS, Installation Instructions Manual, Page: 31 / 52

Commissioning | 31
6 720 805 218 (2013/02) SB625WS/SB745WS
Fig. 29 Securing a cable with a cable clip
Secure all cables with cable clips (part of the control unit standard
delivery) or sleeve in a conduit (if required by code). Perform the
following steps to secure the cables:
▶ Insert the cable clip together with the cable from the top into the slot
in the frame.
▶ Slide the cable clip downwards.
▶ Counterhold.
▶ Flip the lever up.
▶ Fit the back panel.
▶ Refit the cover to the control unit.
▶ Fix the control unit cover with the screws supplied.
6.5 Fitting temperature sensors
The boiler test point is at the top of the boiler body (

Fig. 27 , [1],
page 30).
▶ Measure the depth of the sensor well.
▶ Mark the depth on the temperature sensor set
(lead).
▶ Insert the temperature sensor set as far as it will go into the test
point (to the bottom).
Use the mark to check whether the temperature sensors are correctly
fitted.
▶ Secure the temperature sensor set in the test point with a sensor
retainer.
The plastic coil [2] for keeping the temperature sensors together is
pushed back automatically when it is inserted.
Fig. 30 Inserting the plastic coil into the sensor well
[1] Compensating spring
[2] Plastic spiral
[3] Sensor retainer
[4] Sensor well
▶ Never kink excess lengths of capillaries.
▶ Route the sensor lead through the cable conduit to the control unit.
▶ Connect the sensor lead to the control unit
▶ Complete the commissioning report (

chapter 6.11, page 33).
6.6 Flushing the heating system
To prevent contamination in the boiler, flush the heating system prior to
commissioning.
▶ Flush the system prior to connection to the boiler.
-or-
▶ Isolate the heating flow and return at the boiler.
▶ Connect the heating flow to a water connection.
▶ Connect hose to the heating return of the heating system.
▶ Route hose from the heating return to a drain.
▶ Open connected consumers (e.g. radiators).
▶ Flush the heating system with fresh water until clear water emerges
from the heating return.
▶ Drain the heating system.
NOTICE: System damage through damaged capillaries
or incorrectly fitted temperature sensor.
▶ Ensure that the capillaries are neither kinked nor
squashed when uncoiling and routing them.
▶ Always push the temperature sensor right to the
bottom of the sensor well.
NOTICE: System damage due to incorrect sensor
position!
The safety cut-out (STB) and thermostat (TR) sensors of
the Logamatic 4321 control unit
must be fitted at the
installation site (

picture 27, [1], page 30) on the top
of the boiler.
▶ In the case of third party control units, safety cut-out
and thermostat sensors of third party control units
must be fitted in the instrument bulb/probe socket of
the heating supply (

Fig. 1,[6], page 5) of the
boiler.
▶ Do not change the length of the immersion sleeve.
Standard immersion sleeve used: 3/4"
6 720 615 362-20.1SL
Insert compensating spring [1] between the
temperature sensors to ensure a good contact between
sensor well [4] and sensor surfaces, and thereby a
reliable temperature transfer.
If the heating system contains several heating circuits,
these must be flushed one after the other.
6720615883-32.1RS
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