Publication No. 5105703
29
To Service the Boiler & Component Replacement
5. Unscrew the two hexagonal head screws securing
the pilot (and shield on 80) to the main burner and
remove the pilot assembly, be careful that the pilot
injector does not fall out during this operation.
Unscrew electrode retaining nut and withdraw the
electrode.
6. Replacement is the reverse of removal. On
re-assembly ensure that the spark gap is as illustrated
in Fig. 30.
7. Follow the full commissioning procedure as detailed
in the Commissioning section of these instruction
on page 21.
4.12
Combustion Chamber Insulation
1. Switch off the external electricity supply by
disconnecting the plug at the socket or switching off
the external isolating switch.
2. Remove main burner as described in 4.1 ‘Preparing
the Boiler for Servicing’, operations A, B, C, I, J, K,
L, M.
3. Bend back retaining tabs and replace insulation. It is
necessary to first remove the side insulation when
replacing the rear.
4. Replacement is the reverse of removal.
5. Follow the full commissioning procedure as detailed
in the Commissioning section of these instructions
on page 21.
4.13 Fuse, 4.14 Electronic Control, 4.15 Pressure Switch,
4.16 Overheat Thermostat, 4.17 Boiler Thermostat, 4.18
Gravity HW/Pump Overrun Thermostat, 4.19 Heat
Exchanger Pipe Seal
Note: 4.13, 4.14 & 4.15 are on this page. 4.16, 4.17,
4.18 & 4.19 are on page 30.
The following initial operations 1-3 are necessary to
remove and replace any of the above items.
1. Switch off the external electricity supply by
disconnecting the plug at the socket or switching off
the external isolating switch.
2. Remove controls cover by opening the door covering
the securing screw on the underside of the controls
cover see Fig. 14. Undo securing screw, pull controls
cover forward 10 mm, lower it to release it from its
four side fixings and pull forward clear of the
thermostat knob.
3. Remove control box securing screw and lower control
box.
4.13
Fuse 1 amp
4. The fuse is located on the electronic control and can
be replaced by lifting it from its holder.
5. Replacement is the reverse of removal. Refer to
Figs. 27 & 28.
4.14
Electronic Control
4. Disconnect six way plug, two way plug and electrode
lead from the electronic control. Refer to Figs. 27 &
28.
Disconnect the flying leads of the electronic control
as follows:-
•
white wire from terminal C (3) of the control
thermostat
•
white wire from terminal NC (2) of the control
thermostat
•
brown wire from overheat thermostat
•
blue wire from boiler terminal block connection N
•
green/yellow wire from earth post
5. Release the control by lifting it from the four retaining
lugs.
6. Remove electronic control.
7. Replacement is the reverse of removal.
8. Follow the full commissioning procedure as detailed
in the Commissioning section of these instructions
on page 21.
4.15
Pressure Switch
4. Remove the screw securing the pressure switch to
the bracket in the control box. Lift pressure switch
from bracket.
5. Disconnect the two plastic tubes.
Note: the red tube is connected to the pressure
switch connection identified with a red ring, or adjacent
red spot.
6. Disconnect the three electrical leads, white wire from
terminal No. 1 or NC, orange from terminal No. 2 or
NO and brown from terminal No. 3 or C. Refer to Figs
27 & 28.
7. Replacement is the reverse of removal. Ensure that
the plastic tubes are not kinked on re-assembly.
8. Follow the full commissioning procedure as detailed
in the Commissioning section of these instructions
on page 21.