27
REPLACEMENT OF PARTS
9
9.1
HEAT EXCHANGER
9.2
COMBUSTION CHAMBER INSULATION
9.3
FAN ASSEMBLY
9.4
BURNER
9.5
IGNITION & DETECTION ELECTRODES
9.6.1
GAS CONTROL REPLACEMENT
a) Remove the casing front panel by unscrewing the retaining
screw (on top of panel) and lifting off the casing panel.
b) Remove the sealed chamber front panel (4 screws).
c) Remove the nut securing the burner to the burner locating
bracket (and burner earth wire).
d) Remove the combustion chamber front panel and burner locating
bracket (7 screws). Take care not to damage the insulation.
e) Unscrew and remove the two screws securing the fascia panel
in the upright position and pivot the control panel forwards.
f) Remove the three electrode leads from the electrodes and
unclip the grommet in the bulkhead below the burner to
release the earth, ignition, and detection wires.
g) Unscrew and remove the four screws securing the burner to
the gas manifold and remove the burner by sliding it forwards
with reference to Figure 33.
h) Turn the CH flow and return valves to the closed position to
isolate the boiler. Drain the appliance.
i) Carefully remove the LH combustion chamber insulation panel,
the clip must first be removed from the rear LH lower corner of
the combustion chamber, to reveal an access hole to the heat
exchanger union connections.
j) Using a suitable spanner, unscrew the heat exchanger
connections from inside the combustion chamber.
k) Lift the heat exchanger clear of the two pipes, then remove the
heat exchanger by sliding it forwards.
l) Replace the heat exchanger and re-assemble in reverse order.
Ensure that all joints and seals are correctly re-fitted and re-
commission the system using the procedure in section 5.1.
a) Remove the burner as described in section 9.1 steps (a) to (g).
b) Transfer the ignition and detection electrodes to the new
burner and check that their alignment is as detailed in figure
34.
c) Replace the burner (with reference to figure 33) and re-
assemble in reverse order. Ensure that all joints and seals are
correctly re-fitted.
a) Remove the burner as described in section 9.1 steps (a) to (g).
b) Replace the ignition and /or detection electrode(s) and check
that both electrodes are aligned as detailed in figure 34.
Re-assemble in reverse order. Ensure that all joints and seals
are correctly re-fitted.
a) Remove the casing front panel (as described in section 9.1
step (a) and lower the controls fascia panel after removing the
two retaining screws.
b) Carefully pull off the electrical connector plug from the
multifunctional gas control (Fig. 35)
c) Check that the gas service cock is turned off, and unscrew the
union on the gas cock followed by the four screws securing
the inlet flange of the gas control
d) Remove the four screws securing the outlet flange to the gas
control.
e) Replace the multifunctional gas control and reassemble in
reverse order ensuring that the ‘O’ rings are correctly fitted.
The design of the appliance is such that the combustion chamber
insulation should not require replacement unless mechanically
damaged. It is recommended that the insulation is dampened prior
to removal to prevent dust.
a) To replace the combustion chamber insulation front panel
remove the front panel as described in section 9.1 steps (a) to
(c) and replace the insulation.
b) To replace the combustion chamber insulation side and rear
panels remove the heat exchanger as described in section 9.1
and replace the insulation.
c) Re-assemble in reverse order. Ensure that all joints and seals
are correctly re-fitted and re-commission the system (if
necessary) using the procedure in section 5.1.
It is recommended that a protective mask is worn
when changing or handling the insulation material.
a) Gain access to the fan assembly by following section 9.1
steps (a) to (d).
b) Carefully disconnect the tab connectors on the fan wiring.
c) Disconnect the air pressure switch sensing pipes from the fan,
noting their position.
d) Remove the fan assembly by unscrewing the two screws,
lowering the assembly and lifting it forwards.
e) Replace the fan assembly and re-assemble in reverse order.
Ensure that all joints and seals are correctly re-fitted. (Polarity
is immaterial on the fan connections.)
Before commencing any service operation, ISOLATE the mains electrical
supply, and TURN OFF the gas supply at the main service cock.
It is the law that any service work must be carried out by a registered
person.
9.6
MULTIFUNCTIONAL GAS CONTROL
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