6 720 611 449 GB (03.11)
44
Maintenance
9.3.8
Electrode assembly
B
Refer to section 9.2.
B
Use a new seal if the existing seal is damaged.
9.3.9
Pressure gauge
B
Drain the appliance.
B
Lower the facia. Refer to fig. 57.
B
Twist the pressure gauge head anti-clockwise to
release it from the casing. Refer to fig. 2.
B
Disconnect the capillary head from the rear of the
diverter valve by withdrawing the clip and pulling out
the head. Refer to fig. 58.
9.3.10 Expansion vessel
B
Drain the appliance.
B
Undo the union connection at the base of the vessel.
Refer to fig. 2.
B
Unscrew the top and bottom fixing screws and
remove the vessel.
B
Set the pressure of the new vessel to that required by
the system.
9.3.11 Pressure Relief Valve
B
Drain the appliance.
B
Disconnect the drain pipe from the valve. Refer to
fig. 30.
B
Pull-out the clip securing the valve.
B
Pull-out the valve.
B
Ensure that the replacement valve is fully entered
before fitting the clip.
9.3.12 Burner
B
Refer to section 9.2.
9.3.13 Primary Heat Exchanger
B
Drain the appliance.
B
Check that the gas supply is turned off.
B
Check that the appliance is electrically isolated.
B
Remove the fan assembly complete with the gas/air
tube and mixer assembly. Refer to section 9.3.2.
B
Remove the burner. Refer to section 9.2.
B
Disconnect the sensors. Refer to section 9.3.6.
B
Undo the central heating flow union.
B
Undo the top connection of the pump. Refer to
fig. 57.
B
Undo the grey plastic cap, next to the top pump con-
nection at the base of the heat exchanger.
B
Unscrew and remove the condensate trap. Refer to
section 9.2.
B
Unscrew and remove the two screws securing the
heat exchanger top bracket to the rear panel.
B
Lift up the flue duct, item 271, refer to fig. 2.
B
Pull forward from the top and lift the heat exchanger
from the casing.
B
Transfer components, as necessary, to the new heat
exchanger.
B
Ensure that all the seals are in place and all of the
connections are tight before re-commissioning the
appliance.
Fig. 60
6 720 610 602 - 06.10
