
S
E
R
VICI
NG
& S
PA
R
E
S
INSTALLATION & SERVICING INSTRUCTIONS
40
REPLACEMENT PARTS
6-720-611-730b (12.05)
REPLACEMENT PARTS
Electrode assembly:
Switch off the master switch.
Isolate appliance from the power supply.
Move control panel into service position.
Release 4 screws to remove inner case door.
Pull off the leads from the electrodes.
Unscrew the two fixing screws (B) and carefully
remove the electrode assembly (A).
Replace and re-connect the assembly taking
care not to mislay the inspection window.
Burner:
Check that the gas cock is turned off and the
master switch is in the OFF position.
Isolate appliance from the power supply.
Remove the clips (C) and unscrew the two
bolts.
Remove springs.
Unscrew and remove the 2 hexagon screws
(D) securing the fan.
Slacken fully the rear securing nut (E).
Remove the burner coverplate (F).
Remove the burner skin (G).
Re-assemble the new burner in reverse order,
inspect seal (H) for damage and replace if
necessary.
Check CO
2
settings. See setting the gas/air
ratio.
Primary heat exchanger:
Isolate appliance from the power supply.
Turn off all isolation valves.
Drain down appliance.
Move control and pressure vessel into service
position. To improve access, remove the pressure
vessel.
Remove inner case door.
Remove fan assembly, burner, gas mixing tube.
Disconnect and remove sensors connected
to heat exchanger.
Remove condensate trap.
Remove internal flue elbow and tube from
boiler sump.
Disconnect return pipe union (J) at the base
of the boiler heat exchanger.
Remove plastic nut (K) from the base of the
inner casing.
Remove heat exchanger from inner casing.
Ensure heat conductive paste is used on
sensors when refitting.
Check CO
2
settings. See 'Setting the gas/air
ratio'.
C
D
G
H
B
E
B
A
F
J
K