Technical data

7. Pilot Burner. See Figs. 36 and 40.
Check that the electricity supply to the appliance is turned off.
Remove the cabinet front panel, place the facia and control box
in the Service Position, lower the expansion vessel and remove
the inner casing cover, as described in Section 14.2 a, b, c and d.
Remove the combustion chamber cover as described in Section 14.2 g.
Unscrew the two screws securing the pilot burner to the main
burner. Ease the pilot burner forwards sufficiently to allow a
suitable tool to support it.
Unscrew and withdraw the flame sense electrode.
The spark electrode is held in position with a clip. Ease the clip
backwards and remove the spark electrode and retain.
Unscrew the union nut securing the pilot pipe and ease the pipe
clear. Remove the pilot injector which is a push fit inside the pilot
burner and retain.
Discard the pilot burner.
Fit a replacement pilot burner in the reverse order. Check the pilot
burner settings and spark electrode gap is as shown in Fig. 40.
Reassemble the appliance in the reverse order.
8. Pilot Injector. See Fig. 36.
Remove the pilot burner as described in Section 15.3.7 preceding.
Remove the pilot injector which is a push fit inside the pilot
burner and discard. Fit a replacement pilot injector in the reverse
order. Check the pilot burner settings and spark gap is as shown
in Fig. 40.
Reassemble the appliance in the reverse order.
9. Spark Electrode. See Figs. 36 and 40.
Check that the electricity supply to the appliance is turned off.
Remove the cabinet front panel, place the facia and control box in the
Service Position, lower the expansion vessel and remove the inner
casing cover, as described in Section 14.2 a, b, c and d.
Remove the combustion chamber cover as described in Sections 14.2 g.
Unscrew the two screws securing the pilot burner and the spark
electrode earth lead to the main burner. Ease the pilot burner
forwards sufficiently to allow access.
The spark electrode is held in position with a clip. Ease the clip
backwards and remove the spark electrode. Pull off the spark
electrode cable at the gas valve and discard the spark electrode
assembly.
Fit a replacement spark electrode in the reverse order. Check the
pilot burner settings and spark electrode gap is 4 to 5mm, as
shown in Fig. 40. Reassemble the appliance in the reverse order.
10. Flame Sense Electrode. See Figs. 36 and 40.
Check that the electricity supply to the appliance is turned off.
Remove the cabinet front panel, place the facia and control box
in the Service Position, lower the expansion vessel and remove
the inner casing cover, as described in Section 14.2 a, b, c and d.
Remove the combustion chamber cover as described in Sections 14.2 g.
Unscrew the two screws securing the pilot burner and the spark
electrode earth lead to the main burner. Ease the pilot burner
forwards sufficiently to allow access.
Unscrew and withdraw the flame sense electrode.
Remove the facia as described in Section 15.1.
Carefully pull the lead from the tag on the control board. Remove
the electrode assembly from the appliance and discard.
Fit replacement assembly in reverse order.
Check the pilot burner settings and spark electrode gap is 4 to
5mm, as shown in Fig. 40. Reassemble the appliance in the
reverse order.
11. Safety Temperature Limiter Thermostat. See Fig. 36.
Surface thermostat with vertical 4.8mm tabs.
Check that the electricity supply to the appliance is turned off.
Remove the cabinet front panel, place the facia and control box
in the Service Position, lower the expansion vessel and remove
the inner casing cover, as described in Section 14.2 a, b, c and d.
Remove the facia as described in Section 15.1.
Pull off the two electrical connections to the safety temperature
limiter thermostat.
Unscrew and discard the thermostat.
Fit a new safety temperature limiter thermostat in the reverse
order. The polarity of the connections is not important. Apply a
smear of heat sink compound to the thermostat face.
Reassemble the appliance in the reverse order.
12. Hot Water Sensor. See Figs. 16 and 43.
Surface sensor with vertical 6.3mm tabs.
Check that the electricity supply to the appliance is turned off.
Remove the cabinet front panel as described in Section 14.2 a.
Carefully pull-off the leads to the sensor.
Release the clip and remove the sensor.
Fit a new sensor and re-assemble in the reverse order.
Apply a smear of heat sink compound to the sensor face.
Reassemble the appliance in the reverse order.
13. Heating (Primary) Sensor. See Fig. 36.
Surface sensor with angled 6.3mm tabs.
Check that the electricity supply to the appliance is turned off.
Remove the cabinet front panel, place the facia and control box
in the Service Position, lower the expansion vessel and remove
the inner casing cover, as described in Section 14.2 a, b, c and d.
Pull off the two electrical connections to the sensor.
Unscrew the two screws securing the sensor and discard the sensor.
Fit a new sensor in the reverse order. The polarity of the
connections is not important. Apply a smear of heat sink
compound to the thermostat face.
Reassemble the appliance in the reverse order
36
4-5mm
spark gap
Spark
electrode
Pilot
burner
Pilot burner
fixing
screws (2)
Main burner
Main burner
centre line
37mm
Fig. 40. Pilot burner setting.
Spark
electrode
earth lead