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22
Servicing Instructions - Page 22
C.
Remove screws securing the combustion chamber front
panel and remove panel.
D.
Disconnect the fan supply leads from the connector
adjacent to the fan.
E.
Remove the screws securing the fan mounting plate
leaving in place . the three screws identified with a red
circle or adjacent ‘F’ mark in Fan Plate. Remove
mounting plate complete with fan.
F.
Disconnect the two flexible tubes from the flue elbow or
adapter.
G.
Loosen the two brass securing nuts beneath the flue
elbow outlet and remove the other two. Tilt the flange
and withdraw the elbow. Take care not to damage the
gasket. On vertically flued boilers remove the four brass
nuts and slide the vertical flue adapter up into the flue
duct.
H.
Unscrew the four nuts and lift off the fluehood taking
care not to damage the rope seal. Lower and lift out
vertical flue adapter, if applicable.
I.
Undo the union on the gas service cock outlet.
J.
Unplug the electrical supply leads for the gas control
valve from the control box. See FIG. 29.
K.
Remove the screw securing the gas control valve to its
support bracket. See FIG. 29.
L
Disconnect electrode lead from electrode.
M.
Remove two screws securing the burner assembly to the
bottom of the boiler case and lift out the burner and gas
control assembly.
2.
HEAT EXCHANGER
A.
Working from above and below the heat exchanger use
a suitable cleaning tool and remove all deposits from
between the fins. Slide vertical flue adapter into flue
duct, if applicable.
B.
Refit the fluehood, ensuring that the rope seal is
undamaged and that a GOOD SEAL is made with the
heat exchanger. Fully tighten the four nuts.
C.
Slide the flue elbow into the flue duct or lower flue
adapter and secure to the fluehood using four nuts.
Ensure that the gasket between the fluehood and elbow
or adapter is undamaged and a good seal is obtained.
D.
Reconnect flexible tubes to elbow or adapter.
NOTE: Red tube connects the front aluminium tube in
the upper chamber to the lower connection on elbow or
adapter each being identified with a red ring.
3.
PILOT BURNER
The following operations are only necessary if the pilot flame
is distorted .or the wrong size, i.e. too small.
A.
Unscrew the steel: pilot tube from the pilot assembly.
Take care not to damage the electrode.
B.
Unscrew the two hexagonal head screws securing the
pilot and shield to the main burner and remove the pilot
assembly, be careful that the
pilot injector does not fall out during this operation.
C.
Lightly brush the pilot and its shield to remove any
deposits.
Remove the pilot injector and clean its orifice or replace.
NOTE: Do not use a wire brush or pin to clean injector.
D.
Gently clean any deposits from the electrode.
E.
Refit the pilot injector to the pilot burner and assemble
the pilot to the steel tube.
F.
Secure the pilot assembly to the main burner using two
hexagonal screws.
G.
Fully tighten the union nut connecting the steel tube to
the pilot. Check for gas soundness at this joint by
following the procedure described in the commissioning
section of these instructions, Page 18.
H.
Ensure that the spark gap is as illustrated in FIG. 30.
FIG. 30 PILOT BURNER SPARK GAP TOLERANCES
PILOT FILTER
The pilot burner is protected from blockage by a pilot filter
situated within the gas control valve. The filter is large and
designed to last the life of the gas control valve under normal
operating conditions, it is therefore unlikely to need replacing.
However in the event of pilot filter blockage being suspected
the complete control valve should be replaced.
4.
COMBUSTION CHAMBER INSULATION
A.
Check the combustion chamber insulation for damage. If
damage replace as described under removal
replacement, of boiler mounted units.
5.
MAIN BURNER
A.
Lightly brush any deposits from the top of each blade
and ensure there is no fluff in the entry of the burner
venturi. If on re-assembly the burner flame picture is
incorrect or the correct gas rate or burner pressure
cannot be obtained, remove the burner and gas control
assembly and thoroughly clean the burner. Clean or
replace the injector. In the event of the above
procedures not rectifying the flame appearance,
disconnect the burner from the gas control valve at the
flanged connection and replace the burner and injector.
