SERVICE AND SPARES
6 720 804 532 (2012/09)
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6.8.14 REPLACING CONTROLS
Refer to figure 109.
1. Remove ALL electrical connections from the control PCB including
where cables run through restraints. These can be unclipped from the
plastic moulding noting their position.
2. Carefully remove the system pressure gauge from the fascia by
parting the plastic retaining lugs securing the gauge in place. Take
care not to damage or kink the capillary tube.
3. Remove the code plug. The code plug should be left attached to the
frame of the boiler by its plastic safety thread.
Fig. 109 Replacing the controls (SMPS)
Refer to figure 110.
1. Remove the three screws retaining the front fascia making sure to
support the fascia when removing the last screw.
2. Remove the front fascia.
Fig. 110 Fascia removal (SMPS)
Refer to figure 111.
1. Using a suitable tool, press the button upwards.
2. Slide the control support bracket to the left.
Fig. 111 Control unit release
▶ Remove appropriate cable restraints from the new control unit.
▶ Fit control unit to the boiler. Ensuring the control support bracket is
fully engaged to the right.
▶ Re-connect all electrical connections and system to the new control.
Refer to figure 112.
▶ Replace the fascia to the new control unit remembering to re-connect
the support cable (1).
▶ Secure the system pressure gauge back in the fascia, routing the
capillary as indicated (2)
Fig. 112 Support cable connection
▶ Ensure that the code plug is re-fitted to the new control. If this is not
done, the boiler will indicate an error and will not function.
NOTICE:
▶ Do not replace the control unit if a
CO/CO
2
analyser is
NOT
available.
The control box is supplied within its plastic housing. The
complete unit must be replaced.
6720804530-05.1W
o
2.
3.
1.
6720804530-06.1W
o
1.
1.
1.
2.
1
NOTICE:
▶ After re-assembly, check the CO/CO
2
levels as
described in section 6.6 “Air/Gas ratio setting”.
6720804530-07.1W
o
1.
2.
6720804530-08.1W
o
1
2