Worcester Highflow 400 RSF Installation And Servicing Instructions page 37

burner. Ease the pilot burner forwards sufficiently to allow a
suitable tool to support it.
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. 39.
Reassemble the appliance in the reverse order.
8. Pilot Injector. See Figs. 16, 34, 35 and 39.
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 into the
Service Position 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.
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 discard. Fit a replacement pilot injector in the reverse
order. Check the pilot burner settings and spark gap is as shown
in Fig. 39.
Reassemble the appliance in the reverse order.
9. Spark Electrode. See Figs. 16, 34, 35 and 39.
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 into the
Service Position 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 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 and discard the spark electrode.
Fit a replacement spark electrode in the reverse order. Check the
pilot burner settings and spark electrode gap is 4 to 5mm (0.8in),
as shown in Fig. 39. Reassemble the appliance in the reverse
order.
10. Spark Electrode Lead. See Figs.16,34,35 and 39.
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 into the
Service Position 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 to the main
burner. Ease the pilot burner forwards sufficiently to allow
access.
Remove the pilot tube supply sealing grommet from the front of
the inner casing and retain. Remove the facia as described in
Section 15.1.
Carefully pull one end of the lead from the electrode and ease the
other end off the tag on the spark ignition sequence board.
Remove the lead from the appliance and discard.
Fit replacement lead in reverse order, ensure the inner casing is
sealed correctly. Reassemble the appliance in the reverse order.
Check the pilot burner settings and spark electrode gap is 4 to
5mm (0.8in), as shown in Fig. 39. Reassemble the appliance in
the reverse order.
11. Safety Temperature Limiter Thermostat. See Figs. 9, 16,
Check that the electricity supply to the appliance is turned off.
Remove the cabinet front panel, place the facia and control box
Fig. 39. Pilot burner setting.
Top of main burner rail
Main burner
4-5mm
spark gap
'A'
Spark
electrode
in the Service Position, lower the expansion vessel into the
Service Position 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.
Remove the sealing cover from the inner casing sealing the
capillary tube. Remove the clip and pull the phial from the
pocket on the gas to water heat exchanger. Carefully feed the
capillary tube and phial through the hole in the side of the inner
casing. Pull off the two electrical connections to the safety
temperature limiter thermostat accessible from inside the
control box on the right hand side. Note the position of the
connections. Remove the central clamping nut. Withdraw the
thermostat and thread the capillary through the hole in the
control box. Discard the thermostat.
Fit a new safety temperature limiter thermostat in the reverse
order and ensure the cover is replaced correctly and seals the
inner casing. Ensure the electrical connections are made to the
terminals inside the control box, polarity is not important. Apply
a smear of heat sink compound to the thermostat phial.
Reassemble the appliance in the reverse order.
12. Hot Water Thermostat. See Figs. 9, 16, 40, 53 and 54.
Check that the electricity supply to the appliance is turned off.
Remove the cabinet front panel and place the facia and control
box in the Service Position, as described in Section 14.2 a and b.
37
1mm
Part view on
arrow 'A'
Pilot burner
Pilot
fixing
burner
screws (2)
and 53.